So, looking through the Clymer manual, The instructions for putting on the gasket include 3 sealing washers. The parts list shows two sizes, one with a 13 mm inside diameter and one with an 11 mm. Does it really matter? The manual says that if you leave them off, the cover will leak. Also, do they go over or under the gasket? I know you need to use sealer around the oil passages, and two of the washers are for each end of the set of oil passages on the top. How much of an issue is this? Mine came to me spotting oil from the bottom. When I changed the cam tensioner, I discovered that the right side cover had no gasket at all! It also had a pinched oil seal for the end of the shaft--- the one that funnels oil into the shaft. I replaced that seal, and am about ready to button it up.

Yeah, well, the PO, or at least the last person to open the right side cover made some mistakes. Biggest was there was no gasket at all! They tried to use gasket "maker" but didn't do it right. Anyway, It was leaking pretty well all the time. They also squashed the large O ring under the filter cover, left the other o ring off the filter, and managed to mangle the seal for the end of the drive shaft. I have the shaft seal, and am waiting for the bolt seals. I'll need to figure the size for the big O ring. I've already figured out where the seals go; I just wanted to know if the size difference matters.

Thanks! I will replace that one, too. I just mic'd the slot for the oil filter ring. It looks to be 78x 72mm (the groove dimensions), and the old o ring looks like 3mm thick.