New gas cap seal

It fit good on mine as well but after a few days it seemed to deform/stretch out. Almost like the rubber is a bit soft.

 

Maybe I'll try to boil it for a few minutes, hope it shrinks back down to size and take a good look at the rest of the cap. It's a bit more snug pushing and opening the cap, obviously more than it was with the dry rotted seal that looked very similar to yours. I see other seals online with the yamaha part number 2m0-24641-00 for much more than what Mike XS is sold for but it's a gamble.

 

Thanks for this info. Mine is also looking a little cruddy after 40 years. I'll be purchasing one shortly.

 

No additives other than seafoam a month ago, I use 90 ethanol free gasoline. Maybe I'm just overthinking it. It's still looking like it's going to seal, the gasket is just not tight around the cap as it was when I stuck it on. Kind of hard to see in the picture. Thanks for checking.

 

I've thought about that. Will give it a try.

 

I may have opened my rebuild thread on this forum with a negative comment about the longevity of OEM rubber, however, after cleaning up all of the rubber from the bike, I was dumbfounded to find that most of it was in really great condition. I completely reversed course on my feelings about Yamaha rubber parts and searched out genuine Yamaha and Mikuni rubber where I could if I needed a replacement. However, I see that the Yamaha gas cap gasket has REALLY gone up in price since I bought one. But, I think I would still go for the OEM rubber since I think that the Yamaha stuff is some pretty good shite.

I would be good to see how long the MikesXS stuff lasts as it is very low cost and can be replaced several times before approaching the price of the OEM part.