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

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.

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.



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

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.

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.

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.

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


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

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.

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.

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.

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?

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.

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.

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.

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

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.

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.




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.





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

So I have a few choices to make from my stock of A65 parts:



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.



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.



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



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.



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



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?



Finally, the barrels:



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.)



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



And finally at the Yarmouth Lighthouse.



Tom

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.

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

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.



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

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

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.

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

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

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.