Damned motorbikes (oil leak primary)

[morris]

Have the same problem on the SA. When I bring the oil up to level it’s leaking badly. Once the level has dropped it settles to a drop every now and then but the chain stays wet. Next mod on the list will be an oil seal behind the clutch.

[ellis]

HI all.
Dave burton used to do a great sliding chain case seal that you stick it to the case with silicone sealant and still allowing thee sliding plate to move. Don't know if he still sells them but if he does they are the seal to use.

ELLIS

[JulianS]

A felt washer on the back of the clutch adaptor keeps the oil from leaking at that point. Just thick enought to slightly compress between the adaptor and sliding plate. The SRM clutches come with one. The scrolls not very effective.

[RoyC]

Next mod on the list will be an oil seal behind the clutch.

I got an oil proof foam seal off Dave Flintoft engineering. He specializes in Gold Stars.
Dave Flintoft Engineering
david-flintoft@sky.com
Telephone 01287 638677
 
You have to stick it onto the rear primary case with silicone, then grease the other side so that the sliding plate will slide ok. It cured my leaks.
Also seal the gap in the sliding plate with silicone.

[Peter in Aus]

Have the same problem on the SA. When I bring the oil up to level it’s leaking badly. Once the level has dropped it settles to a drop every now and then but the chain stays wet. Next mod on the list will be an oil seal behind the clutch.

Same here, I keep the oil level as shown in sketch and it leaks very little, not enough to worry about, the chain is always wet so is getting enough oil. and I use ATF

[Colsbeeza]

Thanks Fellas,
  Bill - The scroll is correct, but looks to have slightly less turns than others (See photo from previous post). The additional SRM Felt ring may do the trick, but I do like the idea of Dave Flintoft's foam seal or Dave Burton (Ellis, do you have contact details?). Does the ID of these seals fit the mainshaft OR the scroll itself, as I am not sure I have enough scroll showing to seal on it. I wonder how John Chaterlea's X-section seal fits.? Inside or outside?
  I usually fill about 250ml of oil, then drain the excess through the bottom. It still has the original "standpipe" on the drain, and I usually get about 25mls excess. So the 225ml specified by BSA is about right. I might just leave the oil level to adjust itself for while like Morris, just keep an eye on it.
  It is a bit weird that the clutch chainwheel is 3mm closer to the inner cover than standard, but the scroll is not visible outside the chaincase.!
Cheers
Colin

[ellis]

Hi Colsbeeza.

Sorry I'm getting the Burtons mixed up. It is Dave Flintoft who has the seals. As regards chain case oil capacity SRM recommend 190cc which is enough to lubricate the chain but not enough to Soake the clutch plates. Hope this helps.

ELLIS

[JulianS]

Below are the fitting notes for the Dave Flintoff sliding plate seal.

Like the SRM felt seal on the adaptor it is an effective, low tech and cheap solution.

[JulianS]

  It is a bit weird that the clutch chainwheel is 3mm closer to the inner cover than standard, but the scroll is not visible outside the chaincase.!
Cheers
Colin

If your bike is fitted with the BSA 6 spring clutch then misalignment of clutch chainwheel can happen if the clutch sleeve fitted is from a 1954/55 half width hub swinging arm bike. There is little to distinguish between the 2 parts to the eye.

 The full width hub bikes for 1956 on season were fitted with a modified sleeve offsetting the primary drive about 1/8 inch further out to make room for the fully enclosed chaincase. Also introduced at the time was the steel spacer between chaincase front and crankcase and new cush drive parts.

See brief note below from US importer Hap Alzina.

[berger]

thanks for that julianS I often wondered years ago why my chainwheel was worn, I put it right myself after fitting another chainwheel and lining up the engine sprocket, but this now comes some way to the explanation. my frame is an early 55 s/a but others through history most definitely miss matched many cush drive parts. I first thought the clutch centers were taper ground different. appreciation given.

[Colsbeeza]

Thanks Ellis, I have emailed Dave Flintoff.
Julian, that may explain my problem. I did change to a 4-spring clutch. The Cush Sleeve had a collar thickness of 7.9mm. The Hap Alzina sheet lists several changes, so who knows what sleeve I ended up with. I had believed that a 7.9mm collar was normal for the late models. Thanks for the details of Dave's seal.
Cheers
Colin

[chaterlea25]

Hi All,
Julians info also infers that the cush drive sleeve shoulder must have changed at the same time ??
At this point in time though it can cause lots of headaches

I wonder how John Chaterlea's X-section seal fits.? Inside or outside?

To fit the X ring I removed the centre  part arrowed  in GB's post
I machined up a disc with the centre portion thick enough to cut a groove in to accept the X ring
That was quite a few years ago now but it seems to be still OK

John