Hitchcocks Forum

Is the recommended 15/40 oil better or ATF? The bike had ATF in the clutch when I drained it. It is a 2002 350 Bullet.

hi Dean i,ve used atf and also 20/50 &15/40 they all work i,ve also used straigth 20 in my B.S.A primary cases atb paul.

Thanks Paul. My next question would be what lube would have the least chance of leaking past the rubber seal on the outer case?

The seal will keep all fluids in if its working properly and none if it isn't. If you are having fluid leak out I'd suggest a new rubber seal and a thorough examination of the sealing surfaces. I've used ATF in my primary chain case as its ideal for the task although as previously stated any light oil will do.

Got a new gasket, so hopefully that will take care of the leak. I've got a gallon og ATF sitting on the shelf, so I guess I'll go with that.
thanks,

Hi DEAN---------- the oil seal behind the clutch (ie, fitted on the inner chaincase) can leak if not fitted centrally or its' lip is damaged...Will show as a drip down the gap just where the gearbox chainwheel is...

For what it`s worth; I found ATF for Fords, too grippy, the clutch was either in or out, no smooth take-up. I now use SAE 30, the stuff I use in my 4-stroke lawn mower.

I use stuff that has other uses ie fork oil

The machined face of the outer case is often rubbish. Clean it up on a flat board covered in wet-n-dry and it will be better. The big O ring will last for ages, I just smear some grease in the groove that it sits in. I use ATF and find it a lot better. The rubber seal where the alternator wiring comes out often leaks and can run down to look like the case seal is leaking.