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A65 problem with rings sealing
#812182 06/11/20 7:17 pm
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I rebuilt my A65 Lightning with new Emgo pistons and Hastings (IIRC) rings about 10 years ago, but never put any mileage on it. So I brought it our of retirement last week and took it out for some spirited runs. After some adjustments to side covers (that's another story) I got it oil tight, even when idling on the stand. However, after about a 100 new miles (total now of 300 miles since rebuild), it's now got so much blow by on the right cylinder that it coats the rear tire.

I disassembled it today to find that the rings sealed well on the left cylinder, but not on the right. Following are some photos which seems to indicate that the crosshatching on the left cylinder left by honing are still apparent, though it does not seem to have a blow-by problem. But on the right cylinder, the honing marks are almost non-existent, and the blow-by actually leaves oil on top of the piston.

Could the shop that bored it (+.060) have failed to hone that cylinder sufficiently?

Could the ring gaps being lined up have caused this situation (they seemed quite close to being lined up)?

If I re-hone that side, can I use the same rings over again? Getting new rings even from British Cycle right now is a problem.

[Linked Image from i.postimg.cc]
cylinders showing honing marks
[Linked Image from i.postimg.cc]
Close-up of right cylinder
[Linked Image from i.postimg.cc]
Cylinder head showing oil fouling on right cylinder

Thanks for any advice.


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Re: A65 problem with rings sealing
koncretekid #812184 06/11/20 7:27 pm
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Did you run it in carefully?


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Re: A65 problem with rings sealing
koncretekid #812185 06/11/20 7:32 pm
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one piece or 3 piece oil ring ?
Sometimes a multi-piece Oil ring can get installed wrong .

Re: A65 problem with rings sealing
koncretekid #812186 06/11/20 7:35 pm
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Many years ago when I had my tiger cub rebored, I asked the the old school engineer how long to run it in for. His reply was "Twice up and down the bore"
Last year I asked about running in my brand new GM speedway engine, the engine builder replied "warm it up then thrash it"
So over the space of approximately 43 years the advice has not changed


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Re: A65 problem with rings sealing
koncretekid #812192 06/11/20 8:25 pm
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Pics of rings please , are the RHS rings evenly matt allround? What are the ring gaps? Theres seems to b a lot of vertical scratches in the RHS , and a nasty patch near the top , if it was honed the marks should be clearly visible on the lower cylinder section beyond the ring travel.

Last edited by gavin eisler; 06/11/20 8:28 pm.

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
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Re: A65 problem with rings sealing
koncretekid #812202 06/11/20 9:01 pm
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Even in the left cylinder I don't see much of a cross-hatch honing pattern.
It may be the photo, but it looks messy and not what I would expect.
The right cylinder doesn't show any signs of honing at the same time and I agree with Gavin about the vertical scratches.
Also, are all those thousands of marks in the pic really there? Rust pits perhaps?

I don't know what tool was used to "hone" the left side, but I guess he chose not to repeat on the right side, so left it alone.

I'd suggest having it checked by a proper engineer for bore size/quality against the pistons you have.

Re: A65 problem with rings sealing
koncretekid #812204 06/11/20 9:35 pm
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Quote
If I re-hone that side, can I use the same rings over again?

No.


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Re: A65 problem with rings sealing
triton thrasher #812212 06/11/20 11:00 pm
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Originally Posted by triton thrasher
Quote
If I re-hone that side, can I use the same rings over again?

No.

You can normally get away with it if you are brutal when you bed it in.

Looks like the head gasket was blowing that side so comp would be down, may explain some of it.

Last edited by NickL; 06/11/20 11:01 pm.
Re: A65 problem with rings sealing
Andy Higham #812214 06/11/20 11:37 pm
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A few more photos. Tough to get good photos with the I Phone.

[Linked Image from i.postimg.cc]

Here is the composite gasket I used upside down on the head. Yes there is a small dent in the head adjacent to the bore and a corresponding mark appears on the gasket.
I don't think the gasket was blown. The mottling pattern on the head is unusual to me so I'm blaming it on the composite gasket. It looks kind of like shellac or something that transferred from the gasket. I'll be using a solid copper one on the re-build.

[Linked Image from i.postimg.cc]

Photo of the pistons with the rings. Not much scuffing at all that I can see.

[Linked Image from i.postimg.cc]

I removed the top ring to measure the ring gap here. It's .013".

Originally Posted by Andy Higham
Did you run it in carefully?

Andy, most of my builds go directly from my shop to the dyno, the road race track, or the Salt Flats, so wide open throttle. My road bikes go out on the road and get thrashed as well as I can on these back roads, up and back down the rpm scale. Is that what you would call run in carefully?

Nick, I could do that!

From Koan: "I'd suggest having it checked by a proper engineer for bore size/quality against the pistons you have."

I believe he best pros in the world on BSA's are right here on this forum. That's why I'm asking you guys for advice.

Tom

Last edited by koncretekid; 06/11/20 11:57 pm.

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Re: A65 problem with rings sealing
koncretekid #812218 06/12/20 12:47 am
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Measure the ring gap in the unworn part of the barrel near the bottom, if its 13 at the top expect it to be tighter at the bottom. If its not massively different then a fresh hone and new rings would do the trick.
Rings are supposed to rotate in operation, if they were all lined up that could just be a chance thing so long as they are free to turn, on a side note check the ring fit in the land, they should be free but not walloping around, if a 2 thou feeler goes in then the lands have taken a beating ( I dont think its that but its an easy check).

Does the bike breath through filters?, the vertical scores would suggest not, or the oil was dirty.


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56 Norbsa 68 Longstroke A65
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Re: A65 problem with rings sealing
koncretekid #812227 06/12/20 4:22 am
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I believe I’ve caused similar issues as you by thrashing a set of standard rings. Following others advice to do this, but I guess one persons idea of giving the bike some hard pulls can vary to another. Does your oil tank stink of gasoline also?

Even with modern rings I prefer to use a running in oil and ride the bike normally.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #812234 06/12/20 7:31 am
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The quickest way to get vertical scratches like that is to leave honing grit on the bore.

After honing, it has to be washed in soap and hot water until the bore surface leaves no mark on a white paper tissue. The bores cannot be cleaned properly with kerosene or solvent.


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Re: A65 problem with rings sealing
Allan G #812235 06/12/20 7:35 am
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Originally Posted by Allan G
I believe I’ve caused similar issues as you by thrashing a set of standard rings. Following others advice to do this, but I guess one persons idea of giving the bike some hard pulls can vary to another. Does your oil tank stink of gasoline also?

Even with modern rings I prefer to use a running in oil and ride the bike normally.

The usual advice is to make the engine pull, in bursts, as soon as possible after first starting it with new rings. I wouldn’t say “thrashing” is a good description of that.


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Re: A65 problem with rings sealing
triton thrasher #812238 06/12/20 9:27 am
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Originally Posted by triton thrasher
Originally Posted by Allan G
I believe I’ve caused similar issues as you by thrashing a set of standard rings. Following others advice to do this, but I guess one persons idea of giving the bike some hard pulls can vary to another. Does your oil tank stink of gasoline also?

Even with modern rings I prefer to use a running in oil and ride the bike normally.

The usual advice is to make the engine pull, in bursts, as soon as possible after first starting it with new rings. I wouldn’t say “thrashing” is a good description of that.

Hi TT, I was making refrence to the previous comment.....

Originally Posted by koncretekid
My road bikes go out on the road and get thrashed as well as I can on these back roads, up and back down the rpm scale. Is that what you would call run in carefully?

Everyone rides differently, I never keep my bikes reving low in a high gear (unless im on the motorway then it'll sit somewhere between 3500/4500 revs), I find this kind of riding is sufficient for running in. I have very good compression on both cylinders, the oil also takes forever to blacken. riding as previously mentioned the oil stank of fuel and the gas milage was pretty poor.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #812241 06/12/20 10:15 am
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Worth having a read of the Hastings Cylinder bore refinishing guide Here.

It mentions that the cross hatch angles should be 45 degrees, the grit should be 220 to 280 and that they cylinders must be washed thoroughly afterwards as suggested. Difficult to tell but your cross hatch may be too shallow?

I guess the question is why only one cylinder is affected, some thoughts on this are:-
- maybe one piston was assembled with plenty of lube whilst the other was dry?
- cylinder honing different between cylinders, maybe wrong cross hatching?
- possible head gasket oil leak in one cylinder causing running in issues?

I would re hone the bores, use a dry assembly with the old rings and give it a hard run in.

Last edited by gunner; 06/12/20 10:24 am.

1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
gavin eisler #812269 06/12/20 1:04 pm
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Originally Posted by gavin eisler
Measure the ring gap in the unworn part of the barrel near the bottom, if its 13 at the top expect it to be tighter at the bottom. If its not massively different then a fresh hone and new rings would do the trick.
Rings are supposed to rotate in operation, if they were all lined up that could just be a chance thing so long as they are free to turn, on a side note check the ring fit in the land, they should be free but not walloping around, if a 2 thou feeler goes in then the lands have taken a beating ( I dont think its that but its an easy check).

Does the bike breath through filters?, the vertical scores would suggest not, or the oil was dirty.

I've remeasured more carefully today and found that 1" down from top the gap is .012" whilst at the bottom, .010". But the middle ring and oil ring had a whopping .024-.025" gaps. I also measured the bore 1" from the top and the piston front to back at about the mid point using telescoping gauge on the bore and then using my Mitutoyo 6" calipers. I get the piston at 3.006" and the bore at 3.010", so about .004" clearance. I don't have a bore gauge nor a 3-4" mic, so that's as close as I can get.

The bike has original BSA air filters and there's no smell of gas in the oil. Oil was new, less than 300 miles now. It's always possible the oil tank did not get cleaned as thoroughly as it should have, but the oil looks clean. However, the oil that gets deposited on the floor after a run looks dirty but could just be mixed with road grime and then runs off when I park it

I'm taking a ride up to Wolfville today to pick up some new rings, but no sure what brand. The ones I had were 1-piece oil ring, so not Hastings as I would prefer (3-piece oil rings).

Tom

P.S. I thought this forum was supposed to remember that I'm not a robot, but it doesn't seem to.


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Re: A65 problem with rings sealing
koncretekid #812277 06/12/20 2:11 pm
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Re: Robot, might have something to do with your internet cookies....

Only other consideration is were the rings fitted the right way up? Its possible that it might be sealing well enough to stop blow by of fuel getting past the rings but might just be allowing oil to pass one way.

Another ring option is to give Ed V a call, he is a supplier of Total Seal Rings, I have these on a set of his JE pistons. Never had any oil/fuel cross over contamination issues with them....

Another alternative is there is nothing wrong with your piston rings, Infact you have a very good ring seal and its highlighted a problem in your inlet valve guide (I had this when I first fitted the TS Rings, I thought it was poor ring seal but found it was a bad valve guide pulling oil in and causing it to smoke, after having K-liners fitted it solved the problem)


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #812283 06/12/20 2:40 pm
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It looks to me somebody forgot to hone your right cylinder at all, but pistons don't show this blow by. They really look pristine, like they have a good seal with cylinders. This is why I'd check your valves and guides per Allan's advice. I think your head gasket was leaking on this cylinder too.

Re: A65 problem with rings sealing
koncretekid #812285 06/12/20 3:08 pm
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Valve guides are a good call, always worth a check. Depending on the guides used these are sometimes very short lived, before I heard of Kibblewhite I was very wary of " Bronze" guides , they all seemed to be made of a soft rapid wear material, I much preferred iron guides, now running K guides and fairly pleased so far.

Every old A65 head/ valves I have had in my hands had valves that were worn fore and aft, no sign of valve rotation whatsoever, the guides wear the same to match.

Ive run both sorts of oil ring no preference.

Although large at 24/ 25 thou end gaps , motors will run fine like this without major issues, I dont think thats the smoking gun. i would be more concerned about the 10 thou gap top ring, if it has worn at all then that gap was too tight when fitted .

Current thoughts on piston ring end gaps are that its better to have a larger gap on the 2nd ring , 1-2 thou ,more than the top, learned it here from John Healy who had a very interesting link about how this was found.
It might be a good idea to give the head a wee skim to clear up the divot, you dont have to nix it completely if you win back 50 % of the divot with a 5 thou cut that would be a whole lot better., and if possible have the head bolt holes on the top side spot faced, the inner five are easy enough , the outer 4 are a bit more tricky. Solid Cu is a better bet than composite for A65 head gaskets.

4 thou piston clearance at the bottom seem about right , if the top ring only closes 3 thou from bottom to top then the wear is not huge ( 3 thou on the circumference is about 1 thou on the diameter), hopefully a good 45 degree refresh with the right stones will remove most of the wear marks, at 60 thou over you dont have many other options unless you sleeve the bores and start again.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
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Re: A65 problem with rings sealing
koncretekid #812292 06/12/20 4:29 pm
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There is a lot of carbon build up in both combustion chambers for a 300 mile engine


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Re: A65 problem with rings sealing
koncretekid #812294 06/12/20 4:56 pm
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That's right but no burnt oil on the piston's sides at all. This is why I think guides are a culprit.

Last edited by Adam M.; 06/12/20 4:57 pm.
Re: A65 problem with rings sealing
koncretekid #812302 06/12/20 6:43 pm
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Looking closely at the pics again (and those are all we have to go on), for just 300 miles of use, both pistons have a lot of vertical scoring.
Some of those scores are really quite deep. This accords with the vertical scoring clearly evident in the smoother right bore (so easy to see) but I think similar vertical scoring is also present in the left bore (just masked by the rough honing).
As you know, this is indicative of honing grit remaining in the bores.

However, I find it hard to believe that both of those bores were honed in the same way. I'd doubt that the right bore was honed at all. If so, I'm thinking why has so much coarse grit entered the un-honed bore so soon after new build?
Of course some grit from the left bore would be dragged down, to be hurled about in the crankcase maelstrom, to find its way up between the right piston/bore.
Much of the grit would join the general oil circulation, to do its grinding mission on the rest of the engine, unless/until caught by a decent filter - not a pleasant thought. Was an oil filter in circuit?

Again depending on the pics, the top rings appear to be of a different material to the 2nd rings, and can you see how rough the surfaces of the 2 top rings on the left piston seem to be?

I return to your original pics of the bores/honing pattern. It may be just the pic, but the honing pattern in the left bore appears very crude and not what I would consider correct. Is it possible to show that more clearly?

At 300 miles only the left piston shows evidence of blowby, with minor staining of the land above the top ring (blowby to me is combustion gas passing to the crankcase).

However the head does show some indications of oil passing the rings to the right bore, the clean area suggests detonation (or maybe advanced timing) on that side.

Re: A65 problem with rings sealing
koncretekid #812316 06/12/20 9:28 pm
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In 3 hundred miles how many cold starts? could account for carbon, ticklers ( every time you tickle that carb till the gjuice runs out , thats washing oil off the bore) and worn needle jets who knows , , most folk run conservatively over jetted, if oil gets in as well . It couldnt have been too bad the exh v/vs are close in burn temp. To me its a dirty build with a leaky head gasket( seen worse ).
You should be able to eat your dinner with engine components on assembly, fog the air , put up dust sheets, warn the people around, add extra lighting, your preferred tunes, the full bhuna.

Last edited by gavin eisler; 06/12/20 9:53 pm.

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
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MZ TS 250
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Re: A65 problem with rings sealing
koncretekid #812321 06/12/20 10:25 pm
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My personal opinion is the bore was not cleaned properly before assembly. While both bores show signs of striations left over from bits of the honing stone, I shouldn't have to explain that the right bore is by far the worst.

There is no tell tail signs that there wasn't enough piston clearance. Actually it looks like they had plenty of clearance. By the way, you measure the clearance on those pistons 1 to 2 mm up from the bottom of the skirt.

It wouldn't matter what the ring gap was. From what can be seen in the picture the contact face of the right hand set of rings are "toast".

Change the oil. Drain the sump. Clean up the pistons.

Get someone to hone the cylinder with a 180 grit stone (MAX 220). Get the cross hatch as close to 45° as possible. Then wash the cylinder in HOT SOAPY WATER. When you think it is clean do it for another ten minutes, no twenty. YOU CANNOT GET IT TOO CLEAN. AND NO, SOLVENTS WILL NOT DO THE JOB THAT HOT SOAPY WATER DOES!!!

You want a lightly oiled lint free white rag to come out as white as it was before you started!!!!!

The break in process REQUIRES that you build up the dynamic cylinder pressure - you want to do this by putting a moderate load on the rings during the first run through the gears. Do not let it idle!!!!!!! while you put on your helmet, gloves, etc. By putting a light load on the engine you increase the dynamic cylinder pressure which will push the rings out against the cylinder allowing them to seat ("break-in").

It is my opinion that Hastings has caused more grief in the Vintage British community with their universal 220-280 recommendation for honing. Yes, there are professionals have the expertise, equipment and who can hold the tolerance required, they are few and far between. That said, I believe the quality of the rings, or cylinder finish, had little, if anything, to do with this problem.

Last edited by John Healy; 06/12/20 10:27 pm.
Re: A65 problem with rings sealing
koncretekid #812323 06/12/20 10:40 pm
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Another possibility is that one of the rings has a taper internally/externally and has been installed upside down, worth checking for any markings and also standing each ring on a flat surface and see if stands exactly 90 degrees from horizontal.

Last edited by gunner; 06/12/20 10:53 pm.

1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
koncretekid #812373 06/13/20 2:48 pm
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Here's what we know:
The bike was assembled with Hasting rings.
• Hasting's BSA A65 rings, part number 6939, are not taper faced. The top two tings are directional in that they have a chamfer on the back edge of the ring and this should go up. This is clearly shown on the pack the ring are supplied in. The chamfer is to allow cylinder pressure to get behind the ring and push it outward improving break-in and sealing. If installed Unlike the original AE Helpolite rings, which were taper faced, installing the top two rings upside down will not cause the rings to virtually pump oil upward into the combustion chamber. Albeit putting them in upside down will negate the positive effect of sealing offered by the chamfered ring.
• Given from what we can see, the cylinder bore, condition of the face of the rings and piston skirt, exhibit a classic symptom of assembly without proper cleaning. While you can get similar striations when ingesting something from the intake, the ones exhibited are typically related to chips of stone left behind during the honing process.
• As far as piston clearance is concerned engines that go through this syndrome will almost always suffer from detonation. This will impart a lot more heat than the rings can transfer to the cylinder. This heat migrates down the piston and it starts to grow. One of the first places the effects of the additional heat is the area at the top of the thrust face, just below the oil ring. This is one of two places where you will see the early signs that the piston is about to seize. The other in this situation is the area of the pistons skirt just for-and-aft of the wrist (gudgeon) pin (often called a 4 corner seizure - it must be noted that a 4 corner seizure in an engine that has a fixed wrist pin is a different problem than our free floating pins). There is no sign of potential seizure below the oil ring or indications of a potential 4 corner seizure in While I believe there must have been some additional heat from detonation there certainly appears to be enough (maybe extra) clearance.

Additionally things that are present, but probably had nothing to do with this problem:
• The RH cylinder bore shows signs of glazing.
• The angle of the cross hatch looks shallow, which would hold more oil, making it harder for the rings to seat.
• We don't which oil was used for break-in.
• We have no idea how it was assembled and broken-in.

But those striations on the cylinder bore, rings and piston skirt, however they happened, tell the story.
Just my opinion

Re: A65 problem with rings sealing
koncretekid #812399 06/13/20 9:19 pm
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Thanks for that tutorial, but as I said in my last post, I don't think these were Hastings rings, unless Hastings made the single piece oil control ring. The last few sets of Hastings I got, had the 3 piece oil ring. Also, these rings do not seem to have any taper at all. The new ones shown below have a tapered inside face with the taper intended to be installed up. The oil ring has not top or bottom indicated and appears symmetrical.

A few more photos here. I have a question for John Healy. You said the rings on the right side look like toast. First, the photo above of the two pistons still on the rods is taken from the front, so the left piston in the photo is really the right piston, the one whose rings did not seat. So the "right" one in this photo is the left piston whose rings appear to have seated. So have a look at these photos as I would very much like to know why the rings are "toast".

[Linked Image from i.postimg.cc]

This one shows the marking on the top of the ring indicating that the ring was installed right side up in and answer to a previous comment.

[Linked Image from i.postimg.cc]

[Linked Image from i.postimg.cc]

And two more of the rings removed from piston.

A couple of you have mentioned valve guides. There are new bronze guides from British Cycle Supply and installed and fitted by Ross, who was the top machinist at a local engine shop that rebuilt everything from motorcycle motors to diesel trucks. He probably had well over 20 years experience. The shop was well equipped but sadly has closed, or turned into a body shop, for lack of engine work and Ross has moved away. He also bored and honed the cylinder.

In any case, please advise how leaking valve guides would lead to the extent of blow-by I'm getting?

[Linked Image from i.postimg.cc]

And here are the new rings I got yesterday in a box labeled Cycle Pro. They appear to be cast iron to me so does that change the grade of the grit to hone the cylinder? The old ones appeared to be chrome to me.

One other question related to dry or wet installation. I heard both, but I always oil the rings lightly as I install the pistons.

Tom

Last edited by koncretekid; 06/13/20 9:31 pm.

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Re: A65 problem with rings sealing
koncretekid #812405 06/13/20 9:39 pm
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Tom, you might want to remove your miss placed post from Ben’s A65 thread.

New valve guides puts another slant on things. As do the valves. I have had some valves which measure under size, also some valves which have over size stems and I’ve been able to ream an old guide to suit and it be fine.

Depending how the old guides were removed, damage to the head may have taken place on removal. Thus letting oil slip past.

You understand that the piston on its downward stroke with the inlet valve open draws a vacuum at the carb and pulls the mixture through.... well if theres a decent seal on the rings this will have a stronger effect, if there’s any oil leaks that will get pulled in too. As I say, mine smoked like a pig and I swore it was rings... but it wasn’t it was guides. It isn’t blow by and as Koan? Said unless your getting fuel in your oil it isn’t blow by.

Either bad guides or poor ring sealing.

Regardless of how good someone is supposed to be, ask Rod in the triumph section about supposed decent head shops.


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71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
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Re: A65 problem with rings sealing
koncretekid #812409 06/13/20 10:09 pm
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Originally Posted by Allan G
Tom, you might want to remove your miss placed post from Ben’s A65 thread.

New valve guides puts another slant on things. As do the valves. I have had some valves which measure under size, also some valves which have over size stems and I’ve been able to ream an old guide to suit and it be fine.

Depending how the old guides were removed, damage to the head may have taken place on removal. Thus letting oil slip past.

You understand that the piston on its downward stroke with the inlet valve open draws a vacuum at the carb and pulls the mixture through.... well if theres a decent seal on the rings this will have a stronger effect, if there’s any oil leaks that will get pulled in too. As I say, mine smoked like a pig and I swore it was rings... but it wasn’t it was guides. It isn’t blow by and as Koan? Said unless your getting fuel in your oil it isn’t blow by.

Either bad guides or poor ring sealing.

I tried to edit that post - - deleted the content entirely but the forum kept telling me I hadn't filled in all the required info, so it didn't work. I'll try again.

And yes, I know that as the intake valve opens the piston creates a vacuum that can pull oil into the combustion chamber. But how does that lead to blow-by? The oil drawn in burns or fouls the plug or blows out the exhaust. But if the rings are seated, how does it lead to blow-by?

Tom

Last edited by koncretekid; 06/13/20 10:11 pm.

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Re: A65 problem with rings sealing
koncretekid #812412 06/13/20 10:18 pm
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Hi All,
Looking back at the earlier photo's It looks like (maybe) oil is leaking from the centre head bolt to one or both cylinders??
The BSA head bolt seatings most always get damaged from the bolts being tightened and the thin washers originally fitted
spotface the seatings and fit thick washers, I machine my own from bar stock
A look down the inlet ports will show if there is oil passing down or outside the guide

John

Re: A65 problem with rings sealing
koncretekid #812417 06/13/20 11:10 pm
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If you magnify your pics of the old rings, the surfaces of the rings in the upper pic are as rough as guts. The surfaces of the rings in the lower pic are completely smooth.

Also, clear to my eyes, is that the top rings are of a different material to the middle rings, much shinier (perhaps chrome?)

Re: A65 problem with rings sealing
koan58 #812431 06/14/20 12:58 am
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Originally Posted by koan58
If you magnify your pics of the old rings, the surfaces of the rings in the upper pic are as rough as guts. The surfaces of the rings in the lower pic are completely smooth.

Also, clear to my eyes, is that the top rings are of a different material to the middle rings, much shinier (perhaps chrome?)

Same rings, same location just turned them upside down and took a 2nd photo. It's only an I-phone photo.

Originally Posted by chaterlea25
Hi All,
Looking back at the earlier photo's It looks like (maybe) oil is leaking from the centre head bolt to one or both cylinders??
The BSA head bolt seatings most always get damaged from the bolts being tightened and the thin washers originally fitted
spotface the seatings and fit thick washers, I machine my own from bar stock
A look down the inlet ports will show if there is oil passing down or outside the guide

John

John,
Your analysis makes a lot of sense. That would explain why the pistons show no signs of blow-by and the rings look fine to me, almost unworn. And the oil could be drawn in on intake and the blow back into the rocker box on compression and hence into the crankcases which would explain the massive loss of oil out the breather. That composite head gasket is one that came in a full rebuild gasket set so I used it. I should have annealed the old solid copper one.

And I agree that the washers under the head bolts are not adequate. The ones on the B50 are much thicker so I'll make some thicker ones to fit the A65. And get the head milled (I may do it myself although my largest milling cutter is only 3" in diameter.) I'll check those seats and spotface them as well. I just did that to all the holes in the primary cover and stopped that from leaking under the screw heads.

Tom

Last edited by koncretekid; 06/14/20 1:09 am.

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Re: A65 problem with rings sealing
koncretekid #812436 06/14/20 1:44 am
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Hastings has both chrome top rings and one piece oil rings available. The Hasting BSA kits we distribute have all three rings in grey cast iron with a one piece oil ring. The Cycle Pro rings are made by Grant Ring in California. We also distribute them. The Grant rings in picture are grey cast iron. We recommend using 180 grit.

Re: A65 problem with rings sealing
koncretekid #812444 06/14/20 6:44 am
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Originally Posted by koncretekid
But if the rings are seated, how does it lead to blow-by?

Tom

What I (and some others) are saying is that it isn’t blow-by.

You’ve established no fuel smell in your oil so it cannot be blow-by.

As per johns comment about oil in the port, I honestly cannot remember if mine did or not (I would have looked I’m sure) but it was 10+ years ago. I would suspect there would have been some burnt oil on the rear of the valve.


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68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #812454 06/14/20 8:30 am
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The tool to use is a stiff round dunny brush ( like a bottle brish on sterroids ) with the barrels in a dish of very soapy water


Bike Beesa
Trevor
Re: A65 problem with rings sealing
koncretekid #812460 06/14/20 10:36 am
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A useful piece of kit for determining combustion chamber issues is an old spark plug modified to take an air hose.
Put the piston to TDC and put about 20psi into the cylinder, listen for leaks. You will be able to hear if it is inlet valve, exhaust valve, head gasket or rings (air escaping from breather)


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Re: A65 problem with rings sealing
Allan G #812461 06/14/20 10:42 am
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Originally Posted by Allan G
Originally Posted by koncretekid
But if the rings are seated, how does it lead to blow-by?

Tom

What I (and some others) are saying is that it isn’t blow-by.

You’ve established no fuel smell in your oil so it cannot be blow-by.

As per johns comment about oil in the port, I honestly cannot remember if mine did or not (I would have looked I’m sure) but it was 10+ years ago. I would suspect there would have been some burnt oil on the rear of the valve.

Allan,

I agree that if you have worn valve guides your motor will likely burn oil and may show signs of oil in the combustion chamber and on the spark plug. However, while I don't want to sound contentious (god knows there's enough of that going on now!), my initial issue was excessive oil being deposited on my rear tire and leaking onto the floor after a 25 mile jaunt, which would indicate either a faulty timed breather or blow-by or otherwise too much positive pressure in the crankcase. Of course, a bad job of motor assembly with leaking crankcase and or side covers, leaking main seals or oil being sucked into the motor from the primary or the gear box could also account for oil loss, but that should be evident as excessive oil loss while the bike is parked (would have to be a lot to cover the rear wheel). But as I said, I had no oil loss even while idling up on the work stand.

In any case, disassembly was indicated, and finding oil in the combustion chamber was a pretty good indicator that the problem originated there. I may try just resurfacing the head and using a solid copper head gasket and using the existing rings over again to see if I can learn something here.

Andy, I just saw your response. I usually use a leak down tester to perform that task, but I left my tester back in Colorado where my race bikes are as I usually spend Spring and Fall there. I just ordered a new tester but will have to wait up to a month to get it - - due to the slow-down in mail delivery these days. But I hadn't thought of just pressurizing the cylinder and listening.

Tom

Last edited by koncretekid; 06/14/20 10:58 am.

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Re: A65 problem with rings sealing
koncretekid #812463 06/14/20 11:03 am
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lets call RHS Timing side or TS to save confusion
like wise LHS is Drive side or DS.

The TS cylinder head inlet valve is markedly different in appearance to the DS, oily , clearly not getting as hot as the TS, there may be more than one reason for this, lower cylinder pressure = less heat, or a leaking guide or both.
Unless you are certain that the new " Bronze " guides fitted were Kibblewhite brand I strongly suspect the inlet guide may be worn, or as Allan suggests passing around its OD.

Not seeing oil leaks at idle isnt much of a test, the timed breather works quite well at low speed, if the cases are being pressurised by a bad head joint then the timed breather will cope up to a certain speed , after that it will spew oil mist.

I may have picked this up wrong, koncrete Kid , did you say the RHS of the back wheel gets oily?
IME oil from the timed breather outlet goes to the drive side rear, if you see oil on the TS its more likely that the oil manifold block is leaking.

Last edited by gavin eisler; 06/14/20 11:13 am.

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Re: A65 problem with rings sealing
John Healy #812465 06/14/20 11:20 am
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Originally Posted by John Healy
Hastings has both chrome top rings and one piece oil rings available. The Hasting BSA kits we distribute have all three rings in grey cast iron with a one piece oil ring. The Cycle Pro rings are made by Grant Ring in California. We also distribute them. The Grant rings in picture are grey cast iron. We recommend using 180 grit.

Interesting, John. So the rings I have may actually be Hastings. I had thought so because I used to get my Hastings rings from British Cycle Supply. But the rings I have show no sign of taper to the naked eye.

The top ring appears to be chrome plated. But ring number 2 looks to have a brownish tint, unlike either the top ring or one piece oil ring. So what would that be?

Tom


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Re: A65 problem with rings sealing
koncretekid #812471 06/14/20 12:30 pm
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I like the comment about pressurizing the cylinder. I have been known to take the valve out of my compression gauge and then blow into it. sounds a bit strange but we must do what's necessary. If things are good it will hold pressure for a few seconds. If not, and this gets really weird, stick a hose in your ear and direct the other end to the intake, ex and the crankcase while blowing. Or, get a compressor and relieve yourself from this potentially humiliating scene! Also, how much oil is in the sump? If something out of order in the return she will pump it out from the breather. As you know I run the piss out of my junk and do not get anything from the breather. Good luck. Hope to see you in Sept.! PRT

Re: A65 problem with rings sealing
koncretekid #812506 06/14/20 3:37 pm
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This is a picture of a set of Hastings Triumph 650 rings. The kit comes with a chrome top ring. Not my favorite, but I was not on the committee who specified the chrome top ring to be included. It is a copy of the set of rings supplied with PowerMax Pistons sold by AE Hepolite as their performance series.

Picture of Hastings with chrome top ring

You are not going to solve your problem until you discover what is causing the vertical striations on the piston and the bore. As I said many times above the most probable cause, and most common, is bits of the honing stones used to size the bore. Sure, it could from other sources. Be dirt ingested through the intake, bits of metal from a failing internal part or the likes of bits of left over glass from blasting the parts. What ever it was, it needs to be identified, and removed.

The piston, or bore, should never show signs of vertical striations like seen on these pistons and bore.

As the rings rotate in use, they rarely show signs of the vertical striations. What they do look like is what yours look like. And for them to pass oil is one symptom of the problem you are having with the bore.

Re: A65 problem with rings sealing
koncretekid #812514 06/14/20 4:51 pm
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Upper pic magnified:

[img]https://imgur.com/VSP79PB[/img]


Lower pic magnified about the same:

[img]https://imgur.com/gbLqOpT[/img]


The roughness of the ring surfaces is clear in the well focussed upper pic.

In the lower pic the surfaces appear smooth in comparison, but on examination I think that is an artifact of the pic being out of focus (the camera seems to have focussed on your thumb), though some striations and damage is still detectable through the blur.

In the clear upper pic you can also see where the (likely chrome) upper ring has been confronting the abrasive particles at its top and bottom edges, though it has sustained less damage to its main surface, compared to the other 2 rings (presumably due to its hardness).

Did these rings come from the smooth bore? What were the rings like from the bore with very evident "honing" marks?


Are you able to view your pics on a decent size screen? If not, maybe that is why you're missing some of the detail.

Re: A65 problem with rings sealing
koncretekid #812528 06/14/20 8:05 pm
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To add to Gavin and PRT’s comments on the oil in the sump, this is a sign of blow by, if it’s pumping from the breather then you need to check the pumps ability to suck oil. You do this with the engine running, sump cover removed and a siphon pipe attached to the return pipe and the other side Placed in a measure of oil.

There is a service sheet detailing this.

Adding more to Gavins comment about the oil union, the pre 69 bikes had BSF bolts which were prone to stripping threads when tightened up. The fix is to put a 5/16” Helicoil in. The later UNC bolts appear to be fine. When the threads went on mine however it seemed fine whilst the engine was revving. But leaked oil when on tick over and leaked even more when parked. There’s a nice territory mark outside a post office in sleights near Whitby in Yorkshire with my name on 😂


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
Allan G #812540 06/14/20 8:57 pm
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Originally Posted by gavin eisler
lets call RHS Timing side or TS to save confusion
like wise LHS is Drive side or DS.

The TS cylinder head inlet valve is markedly different in appearance to the DS, oily , clearly not getting as hot as the TS, there may be more than one reason for this, lower cylinder pressure = less heat, or a leaking guide or both.
Unless you are certain that the new " Bronze " guides fitted were Kibblewhite brand I strongly suspect the inlet guide may be worn, or as Allan suggests passing around its OD.

Not seeing oil leaks at idle isnt much of a test, the timed breather works quite well at low speed, if the cases are being pressurised by a bad head joint then the timed breather will cope up to a certain speed , after that it will spew oil mist.

I may have picked this up wrong, koncrete Kid , did you say the RHS of the back wheel gets oily?
IME oil from the timed breather outlet goes to the drive side rear, if you see oil on the TS its more likely that the oil manifold block is leaking.

Yes, it's the timing side that is the problem; oil entering the combustion chamber. It could get there because of a bad valve guide. I haven't disassembled the head yet, but the guides are new bronze guides and the motor has only 300 miles on it since the rebuild.

I don't believe I said RHS of the back wheel but if I did, I meant the left hand or drive side.


Originally Posted by John Healy
This is a picture of a set of Hastings Triumph 650 rings. The kit comes with a chrome top ring. Not my favorite, but I was not on the committee who specified the chrome top ring to be included. It is a copy of the set of rings supplied with PowerMax Pistons sold by AE Hepolite as their performance series.

Picture of Hastings with chrome top ring

You are not going to solve your problem until you discover what is causing the vertical striations on the piston and the bore. As I said many times above the most probable cause, and most common, is bits of the honing stones used to size the bore. Sure, it could from other sources. Be dirt ingested through the intake, bits of metal from a failing internal part or the likes of bits of left over glass from blasting the parts. What ever it was, it needs to be identified, and removed.

The piston, or bore, should never show signs of vertical striations like seen on these pistons and bore.

As the rings rotate in use, they rarely show signs of the vertical striations. What they do look like is what yours look like. And for them to pass oil is one symptom of the problem you are having with the bore.

I don't doubt what you are saying and that I may not have cleaned the cylinder thoroughly enough or that bead blasting media could be the culprit. As I have new rings, I may as well re-hone the cylinders and use the new rings. Of course I'll change the oil, but other than that, I don't know if I'll be able to discover what actually caused the striations. I'll definitely use hot water and soap instead of just a solvent to clean the bores, as that is what I am currently doing with my rebuilds anyway (I built this motor in 2010 so I'm afraid I can't remember just what I did back then); don't know if I can source a "dunny" brush so I'll just have to use a scrub brush.

Do you have an opinion on using oil on the piston and rings upon reassembly?

Originally Posted by Allan G
To add to Gavin and PRT’s comments on the oil in the sump, this is a sign of blow by, if it’s pumping from the breather then you need to check the pumps ability to suck oil. You do this with the engine running, sump cover removed and a siphon pipe attached to the return pipe and the other side Placed in a measure of oil.

There is a service sheet detailing this.

Adding more to Gavins comment about the oil union, the pre 69 bikes had BSF bolts which were prone to stripping threads when tightened up. The fix is to put a 5/16” Helicoil in. The later UNC bolts appear to be fine. When the threads went on mine however it seemed fine whilst the engine was revving. But leaked oil when on tick over and leaked even more when parked. There’s a nice territory mark outside a post office in sleights near Whitby in Yorkshire with my name on 😂

Upon returning from my last run, I checked the oil, and it appears to be at the same level in the tank as before the run, and it doesn't seem to wet sump, but I'll check that again. It definitely shows good return to the tank when running.

The cylinder is marked 68- something which I believe is 26 TPI. I don't remember having any problem achieving the required torque on the bolts, so I'm not going to Helicoil the barrel unless I can't re-torque as specified.

Tom

Last edited by koncretekid; 06/14/20 8:59 pm.

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Re: A65 problem with rings sealing
koncretekid #814876 07/03/20 2:04 pm
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I re-honed the cylinders, bought two new exhaust valves and had a nice 3-angle valve job done, annealed and copper coated an .049" head gasket, reinstalled everything and even added an oil filter.
Honed cyclinders:[Linked Image from i.postimg.cc]
Nice 3-angle valve job including 2 new exhaust valves (one is a rowe, one a GS, because that was all the BCS had in stock in N.S.):[Linked Image from i.postimg.cc]
Installed cylinders - here I have already removed one of the ring clamps which are homemade from hose clamps:[Linked Image from i.postimg.cc]
Cylinders installed with new copper-coated head gasket:[Linked Image from i.postimg.cc]
Oil filter mount - - this unit had failed by blowing out the return spigot, so I threaded it 1/8" NPT and used a close nipple and 90 degree fitting to re-connect (45 degree fitting shown here but did not use that) You can also see the modified Tee to hook up the rocker oil hose while blanking off the original one on the bottom of the crankcase:[Linked Image from i.postimg.cc]
Worm's eye view of the oil filter mounted with attached hoses. The outlet hose passes to the rear of the swing arm without touching it:[Linked Image from i.postimg.cc]
And finally, the socket I modified to be able to torque wrench handles when torquing the head nuts and barrel nuts:[Linked Image from i.postimg.cc]

I re-assembled everything and took it out for a ride in the manner prescribed by most members of this forum. I started it once for about 15 seconds and shut it off. Put on my riding gear and went for a 10 mile ride, but had to return home to put the muffler on which I forgot. Sounded glorious. It puddled oil on the floor again. I took it out for another 22 miles at speeds from 40 to 70 mph, returned home, parked it, and oil ran out on the floor exactly as before. All my refurbishment and no positive result.

I checked oil in the sump this morning (16 hours after my ride) - - 1/3rd cup was all there was. I checked compression and can get 150 psi in both cylinders with 10 good hard kicks. I drained the primary into which I had put 125cc, and I got 100cc out but it may still be draining a bit more.

Adding insult to injury was the new leak-down tester I bought on Amazon.ca which turned out to be a total piece of junk! Could not even get it stop leaking air before I hooked it up.

Other than a failed timed breather mechanism, anybody got any other ideas?????

Tom


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Re: A65 problem with rings sealing
koncretekid #814884 07/03/20 2:46 pm
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Have you determined exactly where the oil is coming from? Use a mirror to check the breather hole. Also check the backside of the sprocket door to see if oil is coming through the seal. You have the chain oiler blocked off?

Re: A65 problem with rings sealing
koncretekid #814889 07/03/20 3:31 pm
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I thought that the original problem was oil fouling in the right hand cylinder, is it still doing this? If not then you may have fixed one problem and found another.

My A65 sometimes dumps a bit of oil on the floor especially after a hard run, difficult to see where its coming from but some possible areas are the alternator lead hole in the chain-case, the rear chain lube hole and the breather as mentioned.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
koncretekid #814895 07/03/20 4:55 pm
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Everything you did looks right and works how it should be working, you have to find a leak, that's all.
Could you make some pictures of an oily engine, after a ride?
To make you happier, I have an oil leak in my Trident, I can't pinpoint for the last 4 years.:)

Last edited by Adam M.; 07/03/20 4:56 pm.
Re: A65 problem with rings sealing
gunner #814896 07/03/20 5:04 pm
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Originally Posted by DMadigan
Have you determined exactly where the oil is coming from? Use a mirror to check the breather hole. Also check the backside of the sprocket door to see if oil is coming through the seal. You have the chain oiler blocked off?

Good idea, I'll try the mirror trick. The problem is, it doesn't leak when sitting on the stand idling. I may have to get someone to hold the throttle open to check that.


Originally Posted by gunner
I thought that the original problem was oil fouling in the right hand cylinder, is it still doing this? If not then you may have fixed one problem and found another.

My A65 sometimes dumps a bit of oil on the floor especially after a hard run, difficult to see where its coming from but some possible areas are the alternator lead hole in the chain-case, the rear chain lube hole and the breather as mentioned.

Looking at the plugs, I don't see any signs of oil. Also, the compression is higher, especially on the timing side. So yes, I may have fixed the leaky head gasket and/or bad ring seating on that side, but the amount of oil being blown out while on a spirited ride is getting on the rear wheel and tire, so not something I can live with. My alternator wire is gooped up well as is the primary chain adjuster and I have blocked the chain oiler.

I'm still thinking blown out the breather because my oil level did go down from the 5 to the 3-3/4 mark on the dipstick, and since the sump (empty when re-started) only holds 1/3rd of a cup and I filled the oil filter, that seems like too much oil loss to be explained any other way. I haven't noticed any smoke, but I'll have to look at that more closely when I restart it to see if I can see any obvious oil leaks.

Tom


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Re: A65 problem with rings sealing
koncretekid #814902 07/03/20 5:27 pm
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Somehow bodge in a bottle, or tube and bottle,, using string or wire, so to catch what comes out of the breather tube. Then you will know.

Re: A65 problem with rings sealing
koncretekid #814909 07/03/20 6:49 pm
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Use ATF in the primary. It works well and since it is red in color you can easily tell if the leak is from the engine or primary.


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Re: A65 problem with rings sealing
koan58 #814937 07/03/20 10:51 pm
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I tried the flashlight and mirror trick but couldn't really see the breather outlet very well. I'll have to take the chain off and try again. In any case, I turned in the throttle stops by 1 full turn, so probably about 2500 rpm, but no oil was leaking out while I watched (about 5 minutes). But after I shut it off, maybe a thimble full of oil dripped off the bottom of the lower chain guard (part of the case). It seems as though it is really a higher rpm leak, with very little leaking at lower rpm, but seems to be accumulating somewhere.

So if the timed breather happens to be in the open position when the motor is shut off, is there some residual oil that accumulates in the camshaft trough that can leak out? This motor is a '65.
Originally Posted by koan58
Somehow bodge in a bottle, or tube and bottle,, using string or wire, so to catch what comes out of the breather tube. Then you will know.

Good idea but hard to do. I'll look as another motor I have to see if there is any way to snake a copper or plastic tube up into the breather hole to confirm the source.

Just saw your post Htown, so I'll try that as well.

Tom

Last edited by koncretekid; 07/03/20 10:53 pm.

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Re: A65 problem with rings sealing
koncretekid #814946 07/03/20 11:42 pm
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Hi Tom,
I am working on an A10 that is doing similar strange things
I found a few issues that while different to the A65 other checks I have to do will be the same

I need to remove the oil tank and devise a way to flush out the return stand pipe, Today I was told of a case where a random piece of gasket goo or other object would get pushed up the return pipe at high revs and partially block the outlet, stop engine and it would fall back down and hide till the next time

Another check to complete is to check the oil pump gasket then the mounting bolts plus the screws that hold the pump together for tightness to make sure there are no leaks

If there is a sump plate with magnetic plug fitted to your A65 either remove the magnet or place the plate with the magnet furthest away from the pickup pipe. I have first hand experience of the magnet causing the ball in the pickup to stick shut

John

Re: A65 problem with rings sealing
koncretekid #814962 07/04/20 12:54 am
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Not possible to bodge a tube into the breather without taking the motor apart. It is just above the gearbox high gear bearing in the back of the main case. Without the chainguard you should be able to see it.
You have an early engine, so you have a seal between the primary and motor? Which way is the seal lip facing? It sounds as though you might be pressurizing the primary through the seal and it has no where to go but out the generator wire hole, sprocket door seal or the chain drip feed. Do you have an inspection cap with the tiny weep hole it it?

Re: A65 problem with rings sealing
koncretekid #814967 07/04/20 1:19 am
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My Thunderbolt has always leaked oil from the primary. Like I posted earlier I use ATF since the engine and primary oil are separate on BSA's and the red color is a dead give away. One place it leaked was the primary adjuster bolt. Fixed that with some thread sealant. But it always dribbled out the back of the case. Mostly I ignored it and checked the fluid level regularly. This spring it got so bad that it was starting to get on the tire. I pulled the primary apart, replaced the seal in the sprocket door and installed a new gasket. I also plugged the chain oiler hole from the case side with silicon and sealed the alternator grommet with some. Dang think still dribbles slightly after a ride. I give up


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Re: A65 problem with rings sealing
htown #814970 07/04/20 2:02 am
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Quote
. Dang think still dribbles slightly after a ride. I give up

the ill-conceived chain oiler hole is also a breather . weres the primary vent hole now ?
when you seal up one hole ... sometimes it just moves the leak .

Some people report that running a vented clutch adjuster plug
allows enough venting without leaking ,

Re: A65 problem with rings sealing
koncretekid #814987 07/04/20 7:16 am
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Get yourself3 different coloured oils
Put ATF in the primary and different coloured oils in both the gearbox & the engine
Take the bike out for a short ride then prk it over a sheet of something white and adsorbent
Look at the colour of the oil\

Sounds silly I know but it is the fastest way to track down a phantom leak
Royal Purple used to make a nice bright purple gear oil which is great for this.

If the leak is mostly rd then the oil is coming from the primary.
If that is the case, drain the primary .
If the oil is polluted with the engine oil ( get a green one if you can ) then you know the primary seal behind the sprocket is leaking

If the oil is green then you have a bottom end problem.
Could be as simple as a leak from the oil manifold

And of course if it is purple then the oil seal on the sleeve gear is the prime suspect, followed by the splines followed by the gearchange lever

Remember that the oil will almost never drip from exactly where it is leaking from because that would make life way too easy.

A long length of hose on the oil tank breather is also a good idea just in cse you have excessive foaming and overflow from the oil tank.


Bike Beesa
Trevor
Re: A65 problem with rings sealing
koncretekid #815174 07/05/20 7:59 pm
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I found primary covers earlier than 70 always prone to leaking because of common opening for oil level and oil dumping with screws holding a cover to the engine. In both cases ( both bottom screws ) oil gets by a gasket and on the threads of screws with only possible way to stop a leak by some seals or gaskets under those screws, which never works 100% in my experience. Have such a cover now, and still no idea how to deal with this problem.

Re: A65 problem with rings sealing
koncretekid #815186 07/05/20 10:05 pm
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Adam,
My cover is apparently later model, with separate level and drain screws. But, I noticed how chewed up the screw seats were, so I spot faced them all to 7/16". Not having a 7/16" end mill, I sacrificed an extra 7/16" bit and ground it to work as an end mill. I also glass sanded the inside of the cover but if you look closely, you'll see how little "meat" there is around the surfaces on the inside of the cover as well as the screw seats on the outside. It's no wonder it's not easy to get a perfect seal. I had already sealed the gasket to the cases with RTV Silicone, so just grease on the outside of the gasket. I also gooped up the screws before I screwed them in .
[Linked Image from i.postimg.cc] Spot facing of screw seats.
[Linked Image from i.postimg.cc]
Inside surface of primary cover.

Tom


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Re: A65 problem with rings sealing
koncretekid #815195 07/05/20 11:00 pm
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Oil can also leak out of the alternator wire tube.

A good move on the cover screws is to use the small copper washers used on the Triumph
unit 500 rocker box allen screws, they are 1/4 washers but have a very small o/d.

Last edited by NickL; 07/05/20 11:01 pm.
Re: A65 problem with rings sealing
koncretekid #815222 07/06/20 7:38 am
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I find fibre washers are good at sealing leaks from the cover screws, the size I use is 1/4 id, 3/8 od and 1/16 thick. These fit nicely under the socket cap heads and dont foul the cover.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
koncretekid #815244 07/06/20 1:25 pm
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Hi Tom, you are lucky to have this cover. Gasket surface on mine is reduced to perhaps 2.5 mm near the oil dumping bolt, oil channel is bypassing gasket on oil level bolt altogether. I will have to use some alu, copper or fibre washers under those screws.

Re: A65 problem with rings sealing
koncretekid #815557 07/08/20 9:10 pm
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To determine more precisely where the oil is leaking from, I devised a "bodge" consisting of a shortened 1/4" barb fitting drilled out as much as possible, screwed into a 90 degree 1/8" NPT pipe fitting with a 3/8" shortened barb fitting with a 3/8" oil line which I epoxied into the breather outlet. I had to remove the rear wheel, chain, and chain guard to be able to snake this into the hole and hold it in place over night for the epoxy to harden.
[Linked Image from i.postimg.cc]
I also discovered that the screw I used to block off the chain oiler was not tight so was able to tighten that as well as a few other things like adding a 7th plate to my clutch (machined off the lining of the first plate and added another plain and friction plate) and replaced a bad rotor. Before the rain came (yay!) I was able to get in another 22 miles of spirited riding and brought the bike back in and placed a container under the newly installed breather hose along with some paper towels. This is the result after about 5 minutes:[Linked Image from i.postimg.cc] The plastic container catches the oil from the breather, and the paper towels show the remainder of leaks.The next photo shows leakage which shows up on the fins of the cylinder head indicating other leakage, which looks to be from the rocker cover.[Linked Image from i.postimg.cc]

Another compression test indicated I was able to achieve about 160 psi after 10 good kicks. I then got out that leakdown tester I said was junk to see if I could make it work. I had to back up one O ring connection with a spark plug washer to stop it from leaking, then discovered that the quick connector just needed to be tightened, and replaced the right hand gauge which failed with one from an old compression tester. Unfortunately, because it reads to 300 psi it was hard to read actual leakage, but the right cylinder actually registered zero leakage. I could not hear any air leakage at 100 psi, anywhere. But the left cylinder did leak, apparently about 10% and that was at the breather as an audible leakage.

So I'm left wondering if the rings on the left cylinder haven't seated yet, or if there is head gasket leakage? Is 54 miles just too little to expect the rings to seat? Is there anyway to determine if it is the rings or the head gasket? The oil I'm using is 20/50W Castrol 4 stroke MC oil type SG/JASO M2, which is the only MC 20/50w oil I can find.

Tom

Last edited by koncretekid; 07/08/20 9:15 pm.

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Re: A65 problem with rings sealing
koncretekid #815559 07/08/20 9:51 pm
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Check it again at 300 and 500 miles. It’s most likely rings haven’t fully seated yet, in 54 miles the bike hasn’t had much time to run in. Providing you anealled your head gasket I doubt it would blow after that mileage. You stand more chance of having leakage at/around the spark plug or from the valve seat.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #815567 07/08/20 10:30 pm
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Sorry if I’ve said this before, but John Healy’s dry assembly and Pete Russell’s (rest his soul) big second ring gap have seen bloody great ring sealing on my bike.

Compression test showing 170 psi, with a 7.25:1 compression ratio ain’t bad.


Amateur Loctite enthusiast.
Re: A65 problem with rings sealing
koncretekid #815572 07/08/20 11:29 pm
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Apart from the breather hole leak, there seem to be leaks from several other areas including the chaincase screws and rocker cover. These leaks may be caused by overpressurization of the crankcases, possibly because of ring blowby and/or problems with the breather disc.

In the short term maybe you could add fibre washers to the chaincase screws and rocker cover studs to stop leaks. In the longer term, it might be worthwhile adding an extra one-way breather/reed valve to the rocker cover to help maintain negative crankcase pressure and stop leaks.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
koncretekid #815576 07/09/20 12:11 am
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You did well to fit that breather catch pipe, thats a tricky access,
the front drip is most likely the primary chain adjuster, the rocker box leak may be oil passing down the stud, plumbers tape will fix that.
Have you retorqued the head after a couple of heat cycles, ?The centre bolt on my head usually nips up a tad more.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: A65 problem with rings sealing
gavin eisler #815578 07/09/20 1:01 am
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Originally Posted by Allan G
Check it again at 300 and 500 miles. It’s most likely rings haven’t fully seated yet, in 54 miles the bike hasn’t had much time to run in. Providing you anealled your head gasket I doubt it would blow after that mileage. You stand more chance of having leakage at/around the spark plug or from the valve seat.
I annealed the head gasket and sprayed it with 2 coats of Permtex copper coat.
Originally Posted by triton thrasher
Sorry if I’ve said this before, but John Healy’s dry assembly and Pete Russell’s (rest his soul) big second ring gap have seen bloody great ring sealing on my bike.

Compression test showing 170 psi, with a 7.25:1 compression ratio ain’t bad.

Allan, I haven't read Mr. Healy's dry assembly, but I lightly coated the cylinder walls and then wiped the oil off with a clean rag leaving just a whiff of oil. Then oiled the skirt only and installed the pistons with rings. My notes are out in the shop, but the ring gaps were all .014" or more.

Originally Posted by gunner
Apart from the breather hole leak, there seem to be leaks from several other areas including the chaincase screws and rocker cover. These leaks may be caused by overpressurization of the crankcases, possibly because of ring blowby and/or problems with the breather disc.

In the short term maybe you could add fibre washers to the chaincase screws and rocker cover studs to stop leaks. In the longer term, it might be worthwhile adding an extra one-way breather/reed valve to the rocker cover to help maintain negative crankcase pressure and stop leaks.

Gunner, I had previously spot faced all the outside screw holes on the primary cover screw seats. I used annealed copper washers on the rocker dome nuts as well as a bit of RTV sealant, but maybe fiber washers would work better. The cover itself was glass sanded; the head surface was only planed with a 12 lathe file. I agree with the possible over pressurization causing some of the leakage; just need the rings to seal unless it's the head gasket. A one-way valve may help, but there shouldn't be that much leakage/pressurization if everything else is tight.

Originally Posted by gavin eisler
You did well to fit that breather catch pipe, thats a tricky access,
the front drip is most likely the primary chain adjuster, the rocker box leak may be oil passing down the stud, plumbers tape will fix that.
Have you retorqued the head after a couple of heat cycles, ?The centre bolt on my head usually nips up a tad more.

Gavin, I had already siliconed the primary chain adjuster on the inside, but maybe still a drip. I used ATF in the primary to see if it leaked red as was suggested. No sign of red oil, and although the primary oil will get dark, I wouldn't think it would in just 22 miles. As far as rocker box studs, I hadn't thought of sealing those and when I remove it to re-torque the head bolts, I'll try that. I've only gone thru 3 heat cycles and 54 miles, so I'll probably just put some more miles on it before I do that to see if the rings will seat better.

Thanks for the suggestions.

Tom


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Re: A65 problem with rings sealing
koncretekid #815632 07/09/20 2:51 pm
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I can see you've done a good job prepping the chaincase so maybe the leaks aren't from the screw holes at all but could be drips from the cylinder head.

Interesting post from a few years ago where someone had a similar problem, see This link


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
koncretekid #815656 07/09/20 6:09 pm
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It looks like the primary chain case is pretty well sealed. It also looks like in the second picture that there is a vertical streak of oil up the primary cover about three quarters of the way back. So that suggests oil is coming from higher up. The oil tank may be venting some oil. Check around where the breather line from the oil tank is venting. When are you checking oil level. Always do it after a ride when oil is hot as it expands. I generally run mine about half way between the marks. Seems like if you run it at the completely full mark some goes out the tank breather. The leak on the fins looks like it is coming from the rocker box cover. It's only on the top fins so unlikely head gasket.
Your compression of 160 psi sounds like the rings are seating to me. I'm still a bit puzzled why the oil comes out the breather.
If it's not using much oil and is running well, I believe I would try to put some miles on it. I've used the same Castrol oil to break in several engines successfully.


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Re: A65 problem with rings sealing
htown #815714 07/09/20 11:50 pm
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Went out today to put some miles on it. 5 miles out, it seized up. I disassembled it this afternoon expecting top end damage of some kind, but not. The left connecting rod is seized to the crank.

Interestingly, the head gasket looks close to blowing on the right side, but that was the side that showed no sign of leakage.
[Linked Image from i.postimg.cc]
The problem is done here:[Linked Image from i.postimg.cc]

Waiting for a pickup, I snapped a nice photo of the girl.[Linked Image from i.postimg.cc]

I'm headed out for a few days, so the rest of the tear down will have to wait.

Tom

Last edited by koncretekid; 07/09/20 11:51 pm.

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Re: A65 problem with rings sealing
koncretekid #815731 07/10/20 1:53 am
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Amazing (and fortunate) that you could seize a rod to the crank without snapping the rod and/or putting it through the piston or the case!

Left big end seizure is typically due to oil starvation and nothing to do with the upper engine.

Inspect the crankcase very carefully. When I trashed a lower (due to oil starvation; I won't go into that here), I didn't notice the two little partial punch-outs at 4:00 and 8:00 until someone else (who knew what to look for) pointed them out. But my conrod was loose, not seized.

Sorry to hear you're "back to the drawing board".


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: A65 problem with rings sealing
koncretekid #815744 07/10/20 6:51 am
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Plus 1, that’ll be oil starvation. I had this, it cost me a rod (probably didn’t have to but I thought it best) set of shells, and being very lucky was able to polish the journal. There was no damage to the journal itself (the seizure happened at very low speed, I knew something wasn’t quite right so started to limp back to camp)

The shells surface melted and spread itself up both sides of the rod effectively wedging the rod against the cheeks of the crank. Fine wet and dry and metal polish cleaned it up fine. I then had the crank nitrided (I don’t think it was long before that hill billy biker did something similar to his race bike and the journal was sound after the bike had been nitrided)

Might be a good time to check that your oil pipes are connected the correct way around.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #815750 07/10/20 8:58 am
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If the journal has the bearing lining stuck to it then hydrochloride acid will remove the Aluminium/tin and not touch the steel crank. Not sure if it work on bronze material. Tip I picked up from Briggs engines with a Aluminium rod which seizes on the crank.

Re: A65 problem with rings sealing
koncretekid #815775 07/10/20 2:22 pm
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Please tell us you don't intend to re use that rod


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Re: A65 problem with rings sealing
koncretekid #815786 07/10/20 3:33 pm
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Very nice looking bike, I craved this Clubman look for a very long time.
When you finally sort out your engine you will have lots of fun with it.
If you have small port head with it it's even more fun riding fast.

Last edited by Adam M.; 07/10/20 3:34 pm.
Re: A65 problem with rings sealing
Andy Higham #815898 07/11/20 4:02 pm
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Originally Posted by kommando
If the journal has the bearing lining stuck to it then hydrochloride acid will remove the Aluminium/tin and not touch the steel crank. Not sure if it work on bronze material. Tip I picked up from Briggs engines with a Aluminium rod which seizes on the crank.
The 2-stroke racer boys used to bring a small bottle of Muriatic acid (dilute hydrochloric) with some swabs with them to the races to clean the aluminum off their bores in case of a seizure.
Originally Posted by Mark Z
Amazing (and fortunate) that you could seize a rod to the crank without snapping the rod and/or putting it through the piston or the case!

Left big end seizure is typically due to oil starvation and nothing to do with the upper engine.

Inspect the crankcase very carefully. When I trashed a lower (due to oil starvation; I won't go into that here), I didn't notice the two little partial punch-outs at 4:00 and 8:00 until someone else (who knew what to look for) pointed them out. But my conrod was loose, not seized.

Sorry to hear you're "back to the drawing board".
Luckily it was a soft seizure as I was slowing for a corner on the 2-lane at the beginning of a planned 120 mile round trip. I could feel the motor slowing down and downshifted into neutral while pulling off into a nice driveway. Also lucky that I was only 5 miles from home and I had the "retriever" set up and ready to come after me - - I had made a rear carrier for my old van with jack-up attached to load up the bike.
[Linked Image from i.postimg.cc]

Originally Posted by Andy Higham
Please tell us you don't intend to re use that rod
Andy, I'm aware of the problem of re-using any aluminum connecting rods if you don't know their history, as aluminum has no defined fatigue life and I have no way of checking them. So I've located some NOS 1971 rods which I believe are better, shot peened finish, but the seller makes no mention of left or right. Did BSA do away with the pee hole in 1971? Or is that hole really necessary?

Tom


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Re: A65 problem with rings sealing
koncretekid #815905 07/11/20 4:36 pm
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The hole is not needed.


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Re: A65 problem with rings sealing
Mark Z #815908 07/11/20 4:58 pm
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Originally Posted by Mark Z
Inspect the crankcase very carefully. When I trashed a lower (due to oil starvation; I won't go into that here), I didn't notice the two little partial punch-outs at 4:00 and 8:00 until someone else (who knew what to look for) pointed them out..

Where are those punch-outs and what are they for, please?


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Re: A65 problem with rings sealing
Nick H #815930 07/11/20 8:11 pm
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Originally Posted by Nick H
Originally Posted by Mark Z
Inspect the crankcase very carefully. When I trashed a lower (due to oil starvation; I won't go into that here), I didn't notice the two little partial punch-outs at 4:00 and 8:00 until someone else (who knew what to look for) pointed them out..

Where are those punch-outs and what are they for, please?

Oh, no, they're not SUPPOSED to be there; they were made by the loose connecting rod. (4:00 and 8:00 are the two closest points to the rod.) My point was that the damage to the case was not obvious at first glance. Fortunately, the camshaft had worn down to the point that the engine quit before grenading


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
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Re: A65 problem with rings sealing
koncretekid #815983 07/12/20 12:40 pm
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ARE YOU USING SYNTHETIC OIL, ARE THE RING CHROME PLATED. EITHER OF THESE THINGS WILL MAKE IT HARD FOR THE RINGS TO SEAT THEMSELVES.


I APOLOGIZE FOR THE USE OF CAPS. I CAN ONLY TYPE WITH MY RIGHT HAND SO USING THE SHIFT KEY IS BEYOND MY CAPABILITES.

The Devil is in the details.

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1965 BSA A65 Lightning Rocket "Clubman" (restored)
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Re: A65 problem with rings sealing
koncretekid #815989 07/12/20 2:32 pm
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Quote
Andy, I'm aware of the problem of re-using any aluminum connecting rods if you don't know their history, as aluminum has no defined fatigue life and I have no way of checking them. So I've located some NOS 1971 rods which I believe are better, shot peened finish, but the seller makes no mention of left or right. Did BSA do away with the pee hole in 1971? Or is that hole really necessary?

Not quite so
Most aluminium alloys will fail by fatigue in around 10,000,000 cycles at ambient temperature on a standard rotating fatigue test.
Note this is a material property & not a finished product property
Elevating the temperature extends this substantially because the stress cracks can self heal by movements along the slip plains.
Much like copper aluminium is FCC and as such has slip plains along all the 111 axis so has 12 active slip planes which is why it is so soft.
But con rods do have a finite life . The last figures I have seen are roughly 150,000,0000 cycles at 5,000 rpm is around 30,000 hours
And once again these are calculated figures and assume no stress raisers and a constant cycling rate and are for a modern 7000 series alloy
In real life you would not want to go above 1/2 those cycles .
Now in the UK where a ride of more than 3 hours will have you in the sea, not such a problem but in places like the USA or Australia not worth the risk .


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Re: A65 problem with rings sealing
koncretekid #815998 07/12/20 4:48 pm
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30,000 hrs with a 50% drop takes you to 15,000 hrs. 5000 rpm is near 70 mph in top for a powerful twin but lets drop that to 35 mph for lower gears and smaller engines.

15,000 hrs at 35 mph give you a life of 525,000 miles.

So USA or Aus is not an issue.

Re: A65 problem with rings sealing
koncretekid #816013 07/12/20 6:14 pm
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Someone on here, possibly Pete Russell, quoted Triumph rod life to be something like 12 hours at 7,000 rpm.

Rod life when you’re turning the crankshaft with a spanner is probably infinite.

How long do rods last when you ride around on the road, mostly between 3,000 and 5,000 rpm? Nobody knows. There will be much less stress on the rods at 5,000 rpm than at 7,000 rpm.


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Re: A65 problem with rings sealing
koncretekid #816016 07/12/20 6:34 pm
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I don’t doubt that WM has something valuable to say here, but the entire calculation is suspect.

To start, I suspect that “roughly 150,000,0000 cycles” is meant to mean 150 million? (or was the extra zero deliberate with misplaced comma?).

So 150,000,000 cycles divided by 5000 rpm (cycles per minute) = 30,000 minutes = 500 hours (only 2 hours a day for 8 months say).

Even adding the extra “0” to make it 1500 million cycles still only makes it 2 hours a day for 80 months (less than 7 years).

It doesn’t make sense to me. And that is assuming 5000rpm. Unless whizzing across Australia at high speed most of the time, as I expect one does on an M20, or racing, it simply doesn’t fit with reality.

I think this analysis is either incorrect and/or completely inappropriate to the use of conrods in our application, irrespective of the country involved.

Re: A65 problem with rings sealing
koncretekid #816017 07/12/20 6:43 pm
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Ok all those cycles, but what is a cycle?


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Re: A65 problem with rings sealing
koncretekid #816020 07/12/20 7:26 pm
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I naively assumed it meant stress cycles?
Wouldn't that be one stretch and compression cycle = 1 360 deg rotation?

Re: A65 problem with rings sealing
koncretekid #816021 07/12/20 7:31 pm
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Rotation at what speed?

Doesn’t the load on the rod vary with the square of rpm?


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Re: A65 problem with rings sealing
koncretekid #816022 07/12/20 7:40 pm
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WM said it in his post, 5000rpm.

Re: A65 problem with rings sealing
koncretekid #816034 07/12/20 9:19 pm
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Nearly all stress analysis is done with perfect specimen - - no nicks, scratches, or any kind of stress risers. Steel fatigue tests show that as long as the stresses are not more than 50% of the ultimate tensile strength, it will last indefinitely. Aluminum on the other hand will fail at some number of stress cycles. The other consideration is impact loading, which is dependent upon the intensity of the stress over the period of time to which it occurs. So a blow up, for example, might induce an extremely high stress over a very short period time, hence it breaks immediately, or not. So buying used connecting rods is always a crap shoot, not knowing what they were subjected to.

Following is an example of a failure of a frame tube on my Bonneville Land Speed BSA B50 partial streamliner after only 2 years and very few hours. Why did this frame member fail? (and upon disassembly, I found 7 cracks in the frame.) The stresses seem very low, and it is steel. But here is the proof that it failed in much fewer cycles than it should have.

[Linked Image from i.postimg.cc]

So the best thing is to buy new. I already have another A65 motor which appears to have low mileage because it is still on original pistons. Do I use the connecting rods, or buy new?

Tom

Last edited by koncretekid; 07/12/20 9:22 pm.

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Re: A65 problem with rings sealing
koncretekid #816043 07/12/20 10:13 pm
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What is the the engine year of production?
I had been using original rods of my 70 A65 for 10 years and some 24000 km without a problem and the next guy is using them now for 3 years, so I believe those late rods are very well made. And I wasn't just puttering around on this bike it had seen 70 - 80 mph quite regularly, sometimes 90 during longer trips.You are just make sure they are not oval at the big ends, that's all.

Re: A65 problem with rings sealing
koncretekid #816047 07/12/20 10:32 pm
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Hi Tom,
The fracture on the frame tube in your photo started at the end of the weld, having the bracket meeting the tube at 90 degrees concentrates the stress , If you had the bracket shaped with convex curved sides so that it meets the tube with a gradual slope the stress is spread along the tube
I believe it is better to add brackets and gussets etc to the side of the tubes rather than to the centre to avoid fractures
I had a frame down tube crack where the steering stop weld ended, along with welding the crack I added metal to the stop so it tapered gradually down to the down tube meeting it further along from the failure point. That was over 20 years ago and its been fine since

Good Luck with the A65 rebuild
John

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Re: A65 problem with rings sealing
koncretekid #816048 07/12/20 10:38 pm
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Replacing the rod is one thing, but the big question is why did it seize in the first place. Likely scenario would be oil starvation. What caused that, worn timing side bush, worn rod bearings or plugged sump trap are some possibilities. I'd also be looking for evidence of piston seizure. Simply installing a new rod and not addressing the root cause of the failure is asking for another blowup possibly with significant damage to the cases the next time. Would highly recommend putting an oil pressure gauge on it when starting it up after rebuild.

Last edited by htown; 07/13/20 12:12 am.

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Re: A65 problem with rings sealing
triton thrasher #816062 07/13/20 3:22 am
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Originally Posted by triton thrasher
Ok all those cycles, but what is a cycle?

A stress cycle for a con rod is actually every time it goes through TDC or BDC .
And there are two different stresses the rod is subjected to.
There is strait compression & tensionwhich is most pronounced at TDC & BDC and then there is a bending moment that is greatest at mid stroke and swaps from left to right depending on weather it is an up stroke or down stroke.

When determining the fatige life of a MATERIAL a rod with a cross section of 1 sq inch x 14" long is supported with 12" hanging out of a chuck and 10lbs hanging off the end of it.
The rod is polished.
The machine is rotated till the rod fails
We used 12" exposed length & 10 lbs for ease of calculations
When we went metric these changed for the same reason but nowhere that I worked had metric gear.

The other stndard test is for a rod spinning between centers with a bearing in the middle
The sample is rotated at fixed speeds then a load is applied to the bearing and is incresed till the rod fails .
The results get plotted on a graph with stress on one axis & number of revolutions on the other, called a S-N curve
Con rods are particularly difficult to do the maths for as the stresses on the rod are highly variable over each cycle.
When selectings a MATERIAL for a cyclic stress application you start by looking at the S-N curve and checking that the MATERIAL you are using is well below the curve for the life proposed service life of the item at the stresses that you have calcualted it will be subjected to.

I really did not want to hyjack the thread, if curious minds need to know more, search " S-N curves for cast (or forged ) aluminium alloys "
The important thing to know is RODS HAVE A FINITE SERVICE LIFE and any BSA on the roads today will be way past the design life of the parts that went into the engine.
Try & find an A 7/10 crank that does not have a nice big fatigue cack right around the drive side journal.


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Re: A65 problem with rings sealing
triton thrasher #816064 07/13/20 3:58 am
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Originally Posted by triton thrasher
Rotation at what speed?

Doesn’t the load on the rod vary with the square of rpm?

It is way way more complicated than that but yes stresses do vary proportional to engine speeds but from memory ( i.e. too lazy to check ) it is exponential relationship not a simple squared one.
At TDC exhaust the stress on the rod is the momentum of the piston & pin.
Similarly at BDC induction stroke.
TDC on compression stroke is of course different as is BDC power stroke.
TDC on ompression/power stroke will be an amplitude change in compressive force and BDC may either be an amplitude change or a compression/tension cycle depending upon weather the charge is still pushing the piston down or the cankshaft is dragging it down at BDC.


Perhaps it is starting to be a little more obvious now why when an engine maker found a bore/stroke ratio that worked, they tended to keep using the same ratio.
Remember when the A 50/65 rods were being designed it was either a trial & error process or days with smoking slide rules


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Re: A65 problem with rings sealing
kommando #816067 07/13/20 4:34 am
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Originally Posted by kommando
30,000 hrs with a 50% drop takes you to 15,000 hrs. 5000 rpm is near 70 mph in top for a powerful twin but lets drop that to 35 mph for lower gears and smaller engines.

15,000 hrs at 35 mph give you a life of 525,000 miles.

So USA or Aus is not an issue.

Actually I made a boo boo because there are 2 stress cycles per revolution, brain was not working.
35 mph might be an average speed in Scotland but it is standing still in OZ.
I average better than than on the WM20.
I doubt you would find many California riders under 70mph unless there was a big car with lights on the roof sitting on their rear wheel. mad
Before I moved out west & my riding drastically reduced I was putting in around 20,000 miles a year on the WM20 .

I should have know better that to throw in some very rough numbers on this list. ohno
Also remember there is idleing time , gear changing and clutch slip and a pile of things that can add lots of cycles over time.
I also did not consult S-N curves particularly as I don't know what alloy BSA actually used so everything was meant to be rough & very approximate .
The take home is whoever advised Tom that aluminium does not have a definite fatigue life was wrong, it does and it is quite short .
It just happened that on a different forum they were discussng rod materials & one of them dropped in link to a paper on a 7000 series rod which was 1.43 x 10 (7) ( can't do superscripts.).
The only alloy I had significant experience with was AS601 which was the only alloy allowed to be used in OZ for cast wheels before we signed our death warrant & joined in the world free trade agreement so now wheels can be made from putty.
AP601 has a stress life of 1,000,000 cycles @ 50% UTS and we made AS601 ingots which had to be certified ( p= primary metal S = secondary metal )
AP 601 is a slight variation of the UK BP 601 and the S variants of both have more specificed impurity tollerances because you get pick up of things like chrome when remelting old wheels.


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Re: A65 problem with rings sealing
koncretekid #816071 07/13/20 7:52 am
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Thanks. So the rod will break after so many cycles, at 50% of the load that would break it in one cycle?

Am I applying 50% of the ultimate tensile strength when I ride the bike?

Pistons are aluminium too, with cycled loads applied to them. So is the crankcase, if it comes to that. Worrying, isn’t it!


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Re: A65 problem with rings sealing
koncretekid #816074 07/13/20 8:34 am
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Now that I have some idea what to search for, this comes up.

[Linked Image from i.postimg.cc]

The flat part of the line on the right is interesting. There’s a stress level that will cause failure in 100,000,000 cycles, which isn’t really very many cycles. Then there’s a lower level of stress which causes no failure at all, no matter how many cycles.

From. https://eurocodes.jrc.ec.europa.eu/doc/WS2008/EN1999_7_Kosteas.pdf


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Re: A65 problem with rings sealing
koncretekid #816075 07/13/20 9:43 am
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"The take home is whoever advised Tom that aluminium does not have a definite fatigue life was wrong, it does and it is quite short ."

Just for the record, I do know that aluminum has a definite fatigue life. What I said was that aluminum does not have defined fatigue life but maybe I should have said that aluminum rods have an unknown remaining fatigue life. My point was that we do not know where we are on that curve when the rods have been previously used; maybe 100,000 cycles or maybe 100,000,000 cycles, or worse yet, maybe they came from a motor that had been raced in anger, or had even been thru a blow-up.

And yes, pistons, too, may be beyond their "best before date", but we usually replace them anyway because they wear out. Rods simply do not show signs of the number of cycles they've been thru. Lots of them for sale on eBay.

I hope to complete the disassembly today and I'm expecting a failed oil pump because the oil I drained from the sump (1/2 cup) was dirtier than the oil that came from the tank, although the oil in the tank would have gone thru the new oil filter I installed.

Is there a thread on this forum about installing an oil pressure port on the pre-'69 motors?

Tom


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Re: A65 problem with rings sealing
koncretekid #816080 07/13/20 11:57 am
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Hi OT, This has been an interesting thread. Sorry for the seizure. I won't comment about the rods but I do have an oil port on my 1966 race bike. I had to do it in order to feed the turbo. Just measure to make sure it is in the right place before the oprv and that it will clear the frame. A 1/8 pipe thread will do the job. Until recently I did not use a gauge because I did not want to know but I was just getting nervous and now use it for testing and will remove it when on the track.
BTW nice bike! With all the spare time I have been giving my street bikes a little long neglected love. Cheers, PRT

Re: A65 problem with rings sealing
koncretekid #816081 07/13/20 12:11 pm
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Id think that installing an oil pressure switch is more of an indicator of whether the pump and OPRV are working as they should, if it comes on just before it goes bang then the damage is already done.

Originally Posted by koncretekid
[Linked Image from i.postimg.cc]


The luggage rack on my former military canam kept breaking in a similar mannor to your frame, the tubing was quite thick too, but with some stress for the mounting plus vibration it would always crack.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
Allan G #816087 07/13/20 1:38 pm
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Originally Posted by Allan G
Id think that installing an oil pressure switch is more of an indicator of whether the pump and OPRV are working as they should, if it comes on just before it goes bang then the damage is already done.


The luggage rack on my former military canam kept breaking in a similar mannor to your frame, the tubing was quite thick too, but with some stress for the mounting plus vibration it would always crack.[/quote]

I can't seem to get PRT's quote on the same reply, so thanks Tom for that. And Allan, too, as having an oil pressure gauge might have saved this one.

So the disassembly didn't have to go far to find the reason for the failure. The oil pump was seizing up as all of the oil pump gear teeth were badly stressed as well as the worm gear on the crankshaft to the point of eventually failing.

[Linked Image from i.postimg.cc]

I didn't do it any favours when removing the inner timing cover, as I withdrew the drive spindle but not the sleeve. I tapped the cover out far enough to bend the shaft slightly, so I can't tell how hard the pump was turning, as I can still turn it now with some difficulty. I do remember taking the end plate off the pump and glass sanding the end plate when I first rebuilt it, so maybe I got it too tight. But it did last about 500 miles as it was.

Tom

Last edited by koncretekid; 07/13/20 1:39 pm.

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Re: A65 problem with rings sealing
koncretekid #816090 07/13/20 1:52 pm
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Hi Tom, was the thick washer in place between the worm gear and the crank pinion?
Failing to remove the tach drive spindle before prying the timing chest is a schoolboy error, smack yourself on the wrist.

Last edited by gavin eisler; 07/13/20 1:55 pm. Reason: changed thrust for thick, in case of confusion

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
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Re: A65 problem with rings sealing
koncretekid #816093 07/13/20 2:25 pm
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Might have taken the 500 miles of chipping away at the teeth, thats some real bad luck. I think your photo is a good reason why these bikes should have an oil pressure gauge. They do survive with very little in the way of oil (or at least end fed bikes seem to)

The worm gear doesn't look too bad, but I would look at fitting a new one just to be sure. If by chance you replace the pump with an SRM unit, the pump comes with a new worm gear as standard. I dont think they used to 15 year ish ago when I bought my first but they were also cheaper. SRM probably had a few "warranty claims" so included one as well as costed for it... no proof of that just a guess.

You might get away with a new spindle and worm gear but this is your call, and how much your willing to spend/risk.

I wouldn't recommend glass sanding it but probably a bit late now. I guess if you do decide to do that it must be before it is stripped, or after it has been assembled on a sheet of glass ensuring all the surfaces are square when it goes together.

Pumps should be tightened to 7ft/lb which isn't very much at all. If using cap screws I prefer to lock tite them, although if using studs (much better method) use aerotight nuts which is what the factory used. I don't know why but they used a normal nut with tabwasher at the drive end, I can't see any harm using an aerotight nut here also.

to add, always tighten the 2 nuts for the pump body before tightening the spindle/drive end.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #816099 07/13/20 3:56 pm
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IMHO that pump is toast. I'd highly recommend biting the bullet and fitting an SRM pump unless you can find a later model cast iron pump but they are hard to come by. Have the SRM unit on my Thunderbolt.


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Re: A65 problem with rings sealing
Allan G #816100 07/13/20 4:00 pm
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Originally Posted by gavin eisler
Hi Tom, was the thick washer in place between the worm gear and the crank pinion?
Failing to remove the tach drive spindle before prying the timing chest is a schoolboy error, smack yourself on the wrist.

Yes the washer was there, but it doesn't look like a BSA original because it is cad plated. How thick is the original?

Originally Posted by Allan G
Might have taken the 500 miles of chipping away at the teeth, thats some real bad luck. I think your photo is a good reason why these bikes should have an oil pressure gauge. They do survive with very little in the way of oil (or at least end fed bikes seem to)

The worm gear doesn't look too bad, but I would look at fitting a new one just to be sure. If by chance you replace the pump with an SRM unit, the pump comes with a new worm gear as standard. I dont think they used to 15 year ish ago when I bought my first but they were also cheaper. SRM probably had a few "warranty claims" so included one as well as costed for it... no proof of that just a guess.

You might get away with a new spindle and worm gear but this is your call, and how much your willing to spend/risk.

I wouldn't recommend glass sanding it but probably a bit late now. I guess if you do decide to do that it must be before it is stripped, or after it has been assembled on a sheet of glass ensuring all the surfaces are square when it goes together.

Pumps should be tightened to 7ft/lb which isn't very much at all. If using cap screws I prefer to lock tite them, although if using studs (much better method) use aerotight nuts which is what the factory used. I don't know why but they used a normal nut with tabwasher at the drive end, I can't see any harm using an aerotight nut here also.

to add, always tighten the 2 nuts for the pump body before tightening the spindle/drive end.

Allen,
The worm gear is not good either. The two centermost gears are shiny and worn, so it will be replaced as well. As for sanding, it was only the end plate that I sanded, which basically just gets rid of the wear from the gears. I did not sand the body, so I can't see how that would affect the rotation other than returning it to more-or-less flat again.

I did check with SRM and they say "none in stock." SC British (Fred DIehl, I believe) has one on eBay, but have inflated the price and shipping right now from the U.S. might as well be from China, as they have just slowed everything down. I'll check with some other sources.

Tom


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Re: A65 problem with rings sealing
koncretekid #816104 07/13/20 4:41 pm
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You can get Hepolite branded oil pumps which appear to be a re-manufactured version of the later cast iron pumps. Jury is still out on whether they are any good and the price is not much cheaper than the SRM pump, but who knows might be OK. Dont know of any suppliers your side of the pond but you can get them on UK eBay.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
koncretekid #816109 07/13/20 5:17 pm
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Sure, CBS sells the Hepolite oil pump. I'm using one for my current Lightning project. You don't get the worm gear though if you buy it with the pump at CBS the price is the same as the SRM! They are iron while the SRM is alloy.
Mine is pumping oil just fine but long term review will have to wait.

Last edited by Nick H; 07/13/20 5:30 pm.

1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: A65 problem with rings sealing
koncretekid #816114 07/13/20 6:56 pm
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I Get you now with the sanding part...

If the rest of the pump is fine, just get the spindle and worm parts, I’m not sure what if any specs are for tooth to body clearance checks, this would be one of the few things that would render the body junk I think, sand the end plates and they will find their own level again.... someone better qualified might tell you different, I’ve always chickened out with pumps and just bought the srm, whilst being happy with it, it’s given me the confidence in its use, as you know it can stuff you very quickly if it’s not right.

I don’t know if this is the one you’ve seen?

https://www.eBay.co.uk/itm/324228138151

When I bought my first one SRM didn’t have one on stock, waited six months and still didn’t have one in ( I’m still on their list now since 2007 😅)

I bought mine from Frank Deihl, only condition was I had to phone him and pay over the phone. Weirdly I never got charged for the call.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #816120 07/13/20 8:23 pm
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The main role of the washer between the worm and pinion is to prevent the worm teeth from chipping .
The pump body is pretty soft , if the tach worm is bent the body is probably distorted.
I didnt know the SRM pump was in short supply, call SRM and see when the next batch is due. Or go for the wassel/ Heppo copy, do you feel lucky?


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: A65 problem with rings sealing
koncretekid #816135 07/13/20 10:44 pm
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I'd rebuild that one, but then, i have plenty of time and some patience. A couple of new bits and it'll be fine.
Fitting a gauge is just fitting a couple of future leak points, if. you're worried about
poor oil pressure, fit a LB20 switch, the old chevvy ones fit, or there's a big choice
just go into a parts store. 1/8npt was standard on heaps of detroit dustbins.

Re: A65 problem with rings sealing
koncretekid #816140 07/13/20 11:32 pm
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In my experience unless the gears go back in as they came from the factory you will probably have binding. I know they can be lapped until matched again but the time expenditure is lengthy.


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Re: A65 problem with rings sealing
triton thrasher #816150 07/14/20 2:11 am
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Originally Posted by triton thrasher
Now that I have some idea what to search for, this comes up.

[Linked Image from i.postimg.cc]

The flat part of the line on the right is interesting. There’s a stress level that will cause failure in 100,000,000 cycles, which isn’t really very many cycles. Then there’s a lower level of stress which causes no failure at all, no matter how many cycles.

From. https://eurocodes.jrc.ec.europa.eu/doc/WS2008/EN1999_7_Kosteas.pdf

No they were being naughty and it looks like they only did 3 measurements n1 , n2 & n3 by virtue of it being 3 strait lines & not a curve.
They have also plotted stress on a log scale & cycles on a linear scale but it is good enough to give a rough idea.
In reality it will slowly taper off to the right but there comes to a point where you are having specimens on the machine for years so they remain the perogerative of PhD students and then it will be a for a very specific alloy.
Frequency of the cycles also has an effect.
If you see a S-N curve that is a single line be a little cautious because they generally plot as a band, not a line.

As for cases surely you have seen stress cracks radiating out from a bearing or bush housing.
You see them a lot on singles around the cam holes

But the take home is replace the rods, even if they look good they could be on the border of letting go and you can not detect the damage AFAIK.
I know x-rays tell you nothing , perhaps a mag resonance will but that was not around in my day.
And remember this is just a material property not the property of the finished rod .

A cracked case is a bot different because it is constrained in all directions ( well should be in any case ) .
As for pistons, the heat factor comes in big time but surely you have seen a piston where the crown has popped off the skirt, usually around the oil scraper ring groove.


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Re: A65 problem with rings sealing
NickL #816171 07/14/20 11:53 am
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Originally Posted by NickL
I'd rebuild that one, but then, i have plenty of time and some patience. A couple of new bits and it'll be fine.
Fitting a gauge is just fitting a couple of future leak points, if. you're worried about
poor oil pressure, fit a LB20 switch, the old chevvy ones fit, or there's a big choice
just go into a parts store. 1/8npt was standard on heaps of detroit dustbins.

Is that a switch for an oil pressure light? Where do you install it? What pressure do they light at?


1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: A65 problem with rings sealing
koncretekid #816225 07/14/20 10:32 pm
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70 onwards motors had a switch fitted. It was around a lb10 device.
If your cases are earlier, you'll either have to drill into the main gallery or use
some ingenuity as to tapping into the pressure line from the pump.
Various courses are open but drilling above the relief valve very a small hole then
opening it out and tapping 1/8npt is the way i went when deriving a source for
end feeding old cases.

Re: A65 problem with rings sealing
koncretekid #823718 09/14/20 12:07 pm
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I finally got all the parts I needed after several delays due to importing of some parts, local sourcing of others, receiving wrong parts, breaking oil pump spindle tach drive in replacement spindle, and life - - grandfathering, etc!

Here is the failed connecting rod bearing and crankshaft journal. Tho journal cleaned up nicely, but since I had a '68 motor under the bench, I chose to rebuild it instead of the '65 motor.
[Linked Image from i.postimg.cc]

[Linked Image from i.postimg.cc]

I found some old photos of the pump that failed, although it's just the repair to the spindle I did 10 years ago and should not have contributed to the failure. I also wanted to point out to Gavin the apparent reason I bent the spindle upon disassembly. You can see that the spindle sleeve is separate from the spindle, and when I followed the BSA workshop manual, it said to remove the spindle but did not mention that the sleeve might not come out with the spindle. So I tried to remove the cover after pulling out the spindle but not the sleeve.

[Linked Image from i.postimg.cc]

[Linked Image from i.postimg.cc]

So the spindle that I bent upon disassembly was probably not the cause of the failure. I do remember that the pump turned over stiffly, but I thought that would loosen up with use - - apparently not!

Tom


Life's uncertain - go fast now!
Re: A65 problem with rings sealing
koncretekid #823727 09/14/20 12:54 pm
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So I have a few choices to make from my stock of A65 parts:

[Linked Image from i.postimg.cc]

The '68 motor appeared to have been rebuilt recently, or at least was still in good shape except for the hardened grease that stuck to everything. The solvent cleaner I use (basically paint thinner) wouldn't touch the stuff. Maybe someone has used bean oil which denigrated into that messy grease. The crank had been turned .020", but the rod bearings, even the main roller looked good, but I did replace them. Only the camshaft D.S. bushing was a problem. It had apparently not been reamed properly and with the cases bolted together, the cam would not turn. I couldn't find a proper reamer locally, and didn't want to buy one so I admit to using the "redneck" reamer shown here to open up the very bottom of the cam bushing where the binding was occurring. It worked great.

[Linked Image from i.postimg.cc]

I wanted to change the breather so I would be able to monitor it. I know that I could have converted to primary cover breathing as I have on my B50's, but I dislike that the clutch material contaminates the motor oil in a very short time if you use the clutch hard. So I tapped the breather hole in the cases and added a few fittings and an exit to get the breather above the motor rather than spraying oil on the real wheel.

[Linked Image from i.postimg.cc]

And another photo showing the exit about the cases which I can connect to a reed valve breather in the future.

[Linked Image from i.postimg.cc]

I like to replace the connecting rod bolts and nuts for insurance, and here are the nuts I was supplied - - the upper nut being the original .525" across the flats, the new ones being .425". Would you use them? My calculations indicated that the smaller nuts would compress the immediate surface of the rod caps to over 50,000 psi. Maybe OK with steel caps, but I wouldn't use them.

[Linked Image from i.postimg.cc]

Checking the new rod bearing clearances with Plastigage shows about .0015".

[Linked Image from i.postimg.cc]

After partial assembly it was out to the outdoor shed to fit the motor into the frame. It is so much easier to fit the motor without the top end. At this point, I was quite happy to get the engine sprocket, primary chain, clutch, and rotor fitted, but I had forgot something that required complete disassembly of these parts. Can you guess what?

[Linked Image from i.postimg.cc]

Finally, the barrels:

[Linked Image from i.postimg.cc]

The top end which had been previously rebuilt was now reassembled and the rest of the bike put back together.

I am quite happy that the motor shows no signs of leakage at the top end, and no oil blowing out of the hose I installed on the breather. You can touch your finger to this hose and feel the pulsing of the timed breather. However, I'm still getting a some oil dripping from underneath that I am at a loss to discover the source. Maybe at higher rpm, the timing breather can't cope with the volume of air, or not really stopping the inflow of air on the uptake of the pistons so more air trying to get out, but it's not coming out the breather as there is no oil showing up beyond the breather; only from underneath. I'm only at about 150 miles from the top end job, so maybe when the rings are totally seated, the problem will diminish.

So here are a couple of photos I took on it's maiden voyage on Saturday. This one at the Fisherman's Memorial on the way to the Yarmouth Light. The Town of Yarmouth can be seen in background (low tide, hence the mud flats.)

[Linked Image from i.postimg.cc]

And another one at John's Cove on the same stretch of road.

[Linked Image from i.postimg.cc]

And finally at the Yarmouth Lighthouse.

[Linked Image from i.postimg.cc]

Tom

Last edited by koncretekid; 09/14/20 12:59 pm.

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Re: A65 problem with rings sealing
koncretekid #823731 09/14/20 1:51 pm
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Looks good Tom!

If you don't mind me saying you took on a lot of effort with permanant changes for the breather when other options are available to you.

You could have tapped that breather hole and fitted a grub screw to blank it off completely. What I did with mine was fit a pipe into the inner timing cover on the dome oppositie the cam pinion. a tube off there works around the clutch and comes out of the inner timing cover, its hidden and easilly repairable and no one would ever know. I'll find/add a photo later. Still its a nice bike you have there.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
Allan G #823737 09/14/20 3:28 pm
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Allan,
I don't think my changes are any more permanent than your solution. I just need to remove the fittings leaving the 1/2" hole in the chain guard area of the cases which I could tap and plug or weld up. You will have to plug up the hole in your inner timing cover. I considered a solution exactly like yours but I would want to use a reed valve breather for sure. I have retained the timed breather for now, but may fit a reed valve in the future.

But, what size pipe did you tap into the timing cover? Without the timed breather or a reed or PCV valve, your motor must suck in 650 cc and blow out 650 cc on each stroke, so the hole may need to be larger than with the timed breather, if in fact, the timed breather actually forms some kind of efficient seal during the upstroke creating a bit of vacuum.

Thanks for the complement on the bike.

Tom


Life's uncertain - go fast now!
Re: A65 problem with rings sealing
koncretekid #823775 09/14/20 9:09 pm
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This is where I located mine, The first hole was incorrect as it stopped me screwing in the fitting, the pipe has a 8mm bore, it exits next to the clutch abutment and hides up the tube and into the tool trap with a filter. You could use a reed valve on the end if you wished. With the covers on you wouldn’t know it was there. I used to have a 1/2” pipe off the rocker cover (the barrel has a 1/2” hole under the centre stud so it breathes happily into the rocker box, Devimead also mounted theirs here. The location is fine, but I found no gain with the half inch pipe Over the 8mm bore tube. I did find some oil go through the pipe through which is why I changed location.

The other (mistake) hole was filled with JB Weld, it’s been like that now for 6 years and hasn’t caused an issue.

[Linked Image][Linked Image]

the exit is bigger than the hole through the cam shaft so it works fine.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
Allan G #823804 09/15/20 1:15 am
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Allan,

I thought you tapped into the top of the inner timing cover, directly into the interior space between the main cases and the timing cover. We could put a larger tapped hole there to get really free breathing. The problem with a small hole and no control is that you turn the motor into an air pump with the associated pumping losses by forcing the 650cc of air in and out thru that small hole at the rpm of the motor. From a performance point of view, this is hp lost. But by adding a reed valve, the pressure should stabilize at a negative pressure and the only air that will pass out will be from blow-by. The negative pressure will assure no oil leaks and the suction on the pistons on the upstroke will be returned by assisting the pistons on the downstroke.

Of course, we're probably only talking about a couple of percent, but in racing, every bit is helpful. For ordinary street use, probably negligible, but the lack of oil leakage on a BSA would be most appreciated.

Tom


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Re: A65 problem with rings sealing
koncretekid #823847 09/15/20 6:44 am
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I believe the factory racers had theirs placed on top, had aesthetics not been a concern I would have done that. I tried a one way valve (not a reed valve) and this hindered more than helped, and a noticeable difference at top end was seen at top end when it was removed. At top end it was also more effective than the timed breather.

The bunn breather has an inlet and and exhaust for the breather so I’m not over convinced about the pumping, of the air is free to pass then it’s not causing a problem. A negative pressure in the crank cases controlled by a timed or reed breather will help reduce
Moisture in the crank cases which will help reduce the acidity within the oil I believe but I personally will take more convincing before I believe it goes beyond this. Someone to put a Race bike/tuned bike on a dyno and Do a direct comparison between with and without the reed fitted. I will then be convinced from the results seen.

I’ve since blanked it off and restored the use of the timed breather, my reasons for going steadier on the bike extend beyond the desire to keep my licence. The use of the standard breather is fine for normal use.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
Allan G #823858 09/15/20 11:09 am
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That being said, do you now have any leakage from your motor and if so, where is it coming from? I ask, because now that I've rerouted my breather hose, and it works with no evidence of oil exiting that hose (now extended to just behind the rear foot peg bracket), I'm still getting some leakage from under the motor which eventually ends up on the drive side of my rear wheel and tire. That was the intention of rerouting so that I could determine that the breather was not the source of any oil leaks. The only thing I can see when up on a lift is that I'm getting some leakage from the oil manifold and or hoses. I used new O-rings on reinstallation of the manifold, but not the BSA ones, so possibly they are thick enough. I'm using ATF in the primary, which is not leaking, and the gearbox oil seems to be maintaining it's level.

I appreciate your comments. FWIW, I use a reed valve breather on my B50 land race bike, which I then run into an exhaust extractor in the exhaust pipe and I do hold the AMA records in three classes with that bike, so I tend to think it works although I've never done back to back comparisons with and without it.

Tom


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Re: A65 problem with rings sealing
koncretekid #823867 09/15/20 12:29 pm
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I just rediscovered this thread and have a couple of 2 cents comments. A number of years ago I did a bunch of different breather experiments with my A-65. One time on the dyno i did back to back tests with a large breather and the stock timed breather. Absolutely no difference. Also, any mist, vapor or occasional drip from the breather goes right on the chain. Sometimes after running I do see a couple of drips on the floor. Get more than that from the pesky oil union.
As far as my own junk at the moment. I am waiting for Mike to wrap up his drag race commitments then we will brainstorm a solution to the handling issue. In the meantime I have been out on the Goldie a few times this week. Pure joy! PRT

Re: A65 problem with rings sealing
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Thanks for adding your findings Tom,

I also have a drop about the size of a 10p piece under the bike from the breather (I think) after a run but that is all. But tHat could be oil from elsewhere. I find the o’rings need replacing every couple of years at the inlet outlet union and that sorts a lot of dripping problems, but I have yet to give the underside of the bike a good clean also. In the past when I’ve changed oil lines etc, it usually stays oil tight for a good while.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #823924 09/15/20 8:56 pm
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Another 2-3 hours of work and a 35 mile ride. No real difference - - still drops oil in spots after the ride. But I had a great ride over some nice 40-60 mph coast roads. Here are a couple taken in Argyle of the "little" fishing boats the poor fishermen have these days.[Linked Image from i.postimg.cc]

[Linked Image from i.postimg.cc]

Other Tom

Last edited by koncretekid; 09/15/20 8:57 pm.

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Re: A65 problem with rings sealing
koncretekid #823928 09/15/20 9:17 pm
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I've got a similar small oil drip which seems to come from somewhere around the gearbox sprocket and stops when the bike engine is stopped.

My current thinking on the source of this leak is that it's one of the following:-
- breather oil being vented onto the chain and excess dripping to the ground
- excess chaincase pressure being vented from the hopefully blocked chain oiler, or alternatly from the oil seal in the sprocket cover trap door.
- possibly gearbox oil venting on to the gearbox sprocket, this may happen if the gearbox sprocket oil seal is loose or gearbox is overfull

I plan to fit a chaincase inspection cover with a tiny breather hole, hopefully this should relieve any excess pressure and stop leaks. If it doesnt I will know to look elsewhere.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
koncretekid #823965 09/16/20 6:57 am
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Gunner the inspection caps on the PCC should have little holes in them anyway (in the breather one) one of them should have a little baffle plate on the inside and a hole as seen from the outside, the baffle plate isn’t really required, I’ve never seen any oil from there.


Koncretekid (Tom) Nova Scotia looks a nice place to visit.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #824078 09/17/20 11:57 am
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The alternator wires can leak oil if not sealed well. My A65 breaths through the primary case only and the chain lasts well and I don't need to check the oil. I have no breathers in the caps. Anything more than an idle the breather hose sucks.


mark
Re: A65 problem with rings sealing
Allan G #824091 09/17/20 4:59 pm
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[Linked Image from i.postimg.cc]

Yesterday after replacing Orings on the oil pipe union, replacing the main oil supply hose, adjusting the clutch, and replacing the fork oil with 30W (lawn mower motor oil was the only non-multi grade oil I could find), I headed northeast to Digby, N.S., home of the Wharf Rat Rally which would have taken place on Labor Day weekend - - cancelled this year.) I took the inland route via route 340 and intended to return by the coast road. But the wind had picked up, remnants of whatever the last hurricane was, and I had to return by the same inland route or get blown into the bay or the woods.

This photo taken in town at the public wharf.

I got home, 132 miles later, and parked the bike for an hour to view this: [Linked Image from i.postimg.cc]

The worst part is the oil on the rear tire, even in the high shoulder rim, as well as on the tire. Maybe I'm being too critical after 132 miles at speeds up to 65 mph, but still not nice.

The good news is that there is no indication of oil any where on the top end as can be seen in the next two photos.

[Linked Image from i.postimg.cc]

[Linked Image from i.postimg.cc]

Today I tweaked all the hoses connections again and removed and added a smear of RTV silicon to the Orings on the oil pipe union connections. I also drained (using the drain plug) and replaced the ATF primary oil; I got about 110 ml of oil out of the 140 I put in, so not bad considering I had the primary cover off yesterday before I refilled. Gear oil seems to just at the tip of the dip stick, and motor oil may be down 1/4 pint.


Originally Posted by Allan G
Gunner the inspection caps on the PCC should have little holes in them anyway (in the breather one) one of them should have a little baffle plate on the inside and a hole as seen from the outside, the baffle plate isn’t really required, I’ve never seen any oil from there.


Koncretekid (Tom) Nova Scotia looks a nice place to visit.

Allan, I have vented inspection caps on my primary and am using ATF so should be able to verify any leakage from that source. I'm pretty sure it is motor oil, but can't tell from where.

I also did a leak-down test today and although the secondary gauge is not the correct one, it's just a 300 psi gauge, both gauges stayed near 100 psi for the test and the leakage (blow-by or head gasket) was very little. If there is leakage, the second gauge should have dropped which it did not.

As for Nova Scotia being a nice place to visit, I thought so too, 47 years ago, and I'm still here. Incidentally, virtually no Covid here so we feel pretty safe, as well.

Tom

Last edited by koncretekid; 09/17/20 5:05 pm.

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Re: A65 problem with rings sealing
koncretekid #824095 09/17/20 5:39 pm
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This amount of oil leaked from my former BSA after 200 km trip I'd consider normal. Remember oil blown from the engine through a breather accumulates on the bottom of the bike and central stand during all this time and leaks from there during a stop.

Re: A65 problem with rings sealing
koncretekid #824097 09/17/20 6:22 pm
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Since you have the union on the breather I doubt that’s your problem.

When I ran a wet clutch it used to loose half of its primary oil then not loose any more, it’d also blacken quickly from the tensioner blade rubber. if you haven’t already block off the breather tube at the back of the primary. If it still leaks check the oil seal and the sleeve tube that’s pushed into the output gear.

... and as mark says, alternator wiring grommet.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 problem with rings sealing
koncretekid #824101 09/17/20 8:06 pm
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Looks like its leaking a bit more than I would like, so some additional things to check:-
- after a ride wipe your hand under the chaincase, any leaks will be apparant by oil being present under the screw heads.
- to stop the drain and level screws in the chaincase from leaking, a fibre washer under the head works well. Also check the screws arent too long as they may be bottoming or there may be crud at the base of the holes stoping them bottoming.
- looks like you have some kind of long drain bolt fitted on the chaincase, why is this?
- block the chain oiler as Allen suggested, this needs a 1/4 cei bolt about 3/4 inch long and fibre washer screwed in from the inner side.
- check the alternator wires as Mark mentioned, I use silicone to seal the grommet and wire.
- fit a new gasket to the sprocket trap door and oil seal.
- maybe the oil is from the gearbox and you need a new gearbox oil seal, I use a gearbox output bearing with one rubber seal plus the sprocket seal.

Its telling that both the primary and engine oil have dropped, I believe that crankcase pressure and oil can get into the primary drive via the drive side bearing despite a seal being present, so it could be that the chaincase is now partially full of engine oil hence the confusion.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 problem with rings sealing
gunner #824103 09/17/20 8:26 pm
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Originally Posted by gunner
.
- looks like you have some kind of long drain bolt fitted on the chaincase, why is this?
- block the chain oiler as Allen suggested, this needs a 1/4 cei bolt about 3/4 inch long and fibre washer screwed in from the inner side.
- check the alternator wires as Mark mentioned, I use silicone to seal the grommet and wire.
- fit a new gasket to the sprocket trap door and oil seal.
- maybe the oil is from the gearbox and you need a new gearbox oil seal, I use a gearbox output bearing with one rubber seal plus the sprocket seal.

Its telling that both the primary and engine oil have dropped, I believe that crankcase pressure and oil can get into the primary drive via the drive side bearing despite a seal being present, so it could be that the chaincase is now partially full of engine oil hence the confusion.

Looks like a later chaincase with the seperate level / drain screws.

The oil in the wheel rim well is not a good sign.
What the others said about oil seals, chain oilers and vented primary.
The stock inspection screws are not vented, I think it was the singles that used them, they fit and work, essential if you blank off the chain oiler.
I just drill a wee hole in the upper cap, after a thrashing it shows signs of oil.
I accept a certain amount of oil after a spirited run, over 70 I can guarantee it, but its not that scattered, and doesnt make the wheel well.

for the oil union, I tried X seals from a chain, didnae work, then I checked it for flatness, of course it was not true, filed it flat, fitted O rings , all good.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: A65 problem with rings sealing
koncretekid #824237 09/19/20 9:09 pm
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[Linked Image from i.postimg.cc]

Rode to Port Maitland beach today about 10 miles from home, but there was nobody there! Kinda cool with a hurricane on the way.

[Linked Image from i.postimg.cc]

Another dozen miles up-the-line to Mavillette Beach with Cape St. Mary's in the background. Both beaches are quite nice in the summer.

[Linked Image from i.postimg.cc]

So after the 45 mile ride, this is what lands on the floor after an hour or so. There is also a wet spot on the other side because I forgot to turn off the gas and the right float was leaking. I think I'm done for now.

As for all the above suggestions, the thing that looks like a drain is my primary chain adjustment bolt, Gunner. And yes, I have the chain oiler blocked off, all new gaskets and seals, a new 21 tooth drive sprocket (don't know how you can live without it unless you ride in a city), the alternator wires and the adjustment bolt are sealed with RTV silicon, and I made a new copper washer for the primary drain screw. The new primary cover gasket is composite with the word "Victor" printed on it. It's still weeping in spite of my having glass sanded the cover and spot faced all the screw seats. I think I'll return to a more standard primary gasket.

It's a pleasure to ride with the 21 tooth drive sprocket up to 80 mph. I don't have a working tachometer so I don't know the rpm, but it sounds great with the 2 into 1 exhaust and the Goldie muffler. The clubman riding position with the clubman bars and big tank feels right, but after the 132 mile ride the other day in high winds, my neck and shoulder were aching. Nothing that a couple of Advil and a cold beer didn't cure.

Ride 'em while you can!

Tom

Last edited by koncretekid; 09/19/20 9:15 pm.

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Re: A65 problem with rings sealing
koncretekid #824238 09/19/20 9:30 pm
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Sounds like you have mostly come to grips with the slightly weepy old girl. Before I started with the racing thing my Hornet was set up much like your bike. Siamese with Goldie muffler and a 20 tooth. The pipe had transformed the behavior dramaticallly. Lots of grunt from lower down compared to the scrambler pipes. I was happy to have standard ergonomics and rode it all over the place. Have fun !

Re: A65 problem with rings sealing
koncretekid #824241 09/19/20 10:03 pm
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Looks like you have sorted out the leak and the spot showing under the sprocket is about the same as I get following a similar ride.

Great looking bike enjoy smile


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
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