Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board A65 problem with rings sealing

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

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".



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.





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?



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

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.

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

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

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.


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

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.

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.

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

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)

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

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.

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

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

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.

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.

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 😂

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.



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?


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

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:
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.):
Installed cylinders - here I have already removed one of the ring clamps which are homemade from hose clamps:
Cylinders installed with new copper-coated head gasket:
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:
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:
And finally, the socket I modified to be able to torque wrench handles when torquing the head nuts and barrel nuts:

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

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?

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.

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.:)

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.



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

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.