Motoscrubs.com

Hey guys,
I have a persistent oil leak I can't get rid of and is getting worse, from behind the output shaft sprocket. After 2000 miles on this engine build, it is leaking enough to be a really good chain oiler, (along with rear wheel, rear fender, and the bottom of the engine cases, and dripping to the floor). What is the best known remedy for this problem? The way I remember it, that output shaft bearing behind there is the one that I left the outer seal of the new bearing in place... I also have tried an O-ring on the flange of the sprocket back-side.
Any thoughts?

Bruce

Too high an oil level will do this. Also the pen steel washer needs to be in there. Nigel Lacey makes a good oil seal for the job.

Sorry,my old brain was thinking of the pushrod seal, however the high oil level comment is valid. The motor takes a long time to heat up and is not used for long runs normally , so a lower level works for me. Check the engine breather is clear and not flatenned somewhere, remove the clutch inspection plate and blow down the breather pipe to check its clear.

Hi Bob,
Thanks for the response
My breather tube is in good shape, but I use a pcv valve in that hose...maybe that's not working out so well. Think I'll remove it and see if that helps any.
I also need to check my oil level to see if it's increasing in volume.
Just to be clear, this oil leak is not a normal problem to deal with?

Bruce

I did have a good leak in this area,but a lower oil level seems to have done the job. !0 days bombing around the IOM and 15 laps of Jurby and there is no mess and little oil used.

If you take the sprocket off and clean things up, you can blow some talcum powder in the area to see where the oil is seeping from- either between the shaft and the bearing or the bearing and the casting. Loctite makes a 'wicking' thread locker- they call it capillary action- it's Loctite 290, green.
http://www.loctiteproducts.com/tds/T_LKR_GREEN_tds.pdf
If you can get it to wick onto the surfaces that are leaking it may work- they advertise it as a threadlocker when it's not possible to disassemble and use the more common threadlocker.
The Loctite 290 will release with heat, but a little bit goes a long ways, and the excess isn't hard to clean off.
Good luck.
Rick

I changed my primary sprocket awhile back. The new one from Syds obviously fit the spine correctly, but the outer diameter was smaller than the original. In looking closer the original has a reverse spiral cut in to the surface that keeps oil "tracking" back into the motor and no seal is present.
I made a simple brass sleeve on my lathe that both brought the OD back to the original size and I added a reverse spiral groove. NO Seal NO leaks.
You may check the OD of the primary sprocket you have. I'll get a picture and post up tonite of the original with spiral groove and OD.

Mike Mc

Hey Rick,
Thanks for the input... I like the technique of tracking a small seepage. I'll keep that in mind for when the occasion arises, this leak is a gusher.

In the spirit of fair information...
When I removed my side cover to see what is really going on, although the primary sprocket is (also) leaking, my main leak is at the clutch plunger seal. Not hard to tell either....
I already had a seal for that in route from guzzino.com to just redo that while I was working on the primary sprocket leak. Looks like it's going to be the other way around.

Mike,
I'm interested in your information about your primary sprocket, measurements, etc. Maybe something there that will improve my leaky fit.

Thanks,
Bruce

So the OD of the sprocket is 1.100 ( 27.94mm)
Attached is a picture.
Hope this helps.

Mike Mc

Hi Mike,
Thanks, yeah, that's what mine looks like too. It measures 1.097 in.

Bruce