Some of you may have read about the problems we've been having in curing an oil leak from the rear cylinder on Stephanie's (now mine) 2001 750SS. Oil would pool in the finned area at the top of the crankcases then drip down when the quantities became sufficient.

Well after I put it back together last time the leak was worse than ever - I tried a different kind of gasket cement and it didn't work at all in this application. Oil started to appear on the first outing.

Today I decided to try one more time to stem the flow and this time I noticed something different in the gasket compared to the picture of a base gasket in the Haynes manual.

There's an o ring in the rear oil passageway but the hole in the gasket was not large enough for the o ring to reach the crankcase and cylinder base; the o ring was just resting on and sealing the top of the gasket surface.

What I saw in the picture in the manual was that the hole in this other gasket was large enough that the o ring sat in the hole, and was able to seal the surface.

I had already taken the Dremel to my gasket this morning thinking that was the only way it could work, then found confirmation in the picture.

Here is a picture I took of both a standard gasket and the one I'd modified. The top hole in each gasket is the oil drain hole, and the one on the left is unmodified. The o ring now fits into the hole I Dremeled.



I've got it back together and running now but it'll take a few rides to know if the cure is permanent.

You've hit on it. The O ring HAS to fit 'into' the gasket hole. Very important!

So far, so good! The bike ran flawlessly over the weekend at the rally in Mont Tremblant and it looks like the leak is cured, for the moment anyway.

Time will tell how long it holds but I'm optimistic!