Hello, I have a 1980 Yamaha XS400 Special that I have owned since 1986...Lately, it has started this irractic idling and racing engine, I have narrowed it down to a vacuum leak from a shaft seal on the carburator...On each carb there is an E-clip, fibre washer and behind a small black seal which is old and dried out, the source of my vacuum leak..I went to our local Yamaha dealer to try to order replacement seals but was told that the there was no parts listing for that seal because it was a factory installed part and I would have to order an entire new carb to fix my problem...Does anyone have a more realistic solution to my vacuum leak? Is there an aftermarket seal available to fit my application? I realize I could use an O-ring in a pinch but I would rather find an actual double lipped seal that the factory used...Here is a picture link to the shaft where the leaking seal is located http://members.shaw.ca/mackeil/

Thank you,

Stacey

Vancouver Island, Canada

Hello, I have a 1980 Yamaha XS400 Special that I have owned since 1986...Lately, it has started this irractic idling and racing engine, I have narrowed it down to a vacuum leak from a shaft seal on the carburator...On each carb there is an E-clip, fibre washer and behind a small black seal which is old and dried out, the source of my vacuum leak..I went to our local Yamaha dealer to try to order replacement seals but was told that the there was no parts listing for that seal because it was a factory installed part and I would have to order an entire new carb to fix my problem...Does anyone have a more realistic solution to my vacuum leak? Is there an aftermarket seal available to fit my application? I realize I could use an O-ring in a pinch but I would rather find an actual double lipped seal that the factory used...Here is a picture link to the shaft where the leaking seal is located http://members.shaw.ca/mackeil/

Thank you,

Stacey

Vancouver Island, Canada

http://www.mikesxs.net/products-75.html#products

Part #48-5021

and Part #48-5022

Hey Mackeil, I have a 1976 XS500C and I think I may be having some similar issues. I just cleaned the carbs out and switched to K&N pod filters instead of the stock filter, and I am experiencing erratic idling (mainly while riding) and occasional engine racing (mainly on startup, when it's still choked). When I reassembled the carburetor I replaced the gaskets, but that was it. Do you think this could be the same issue? I'd like to know how this worked out for you if you were able to get the replacements! Also, which part is the E-clip? I can't quite place it...The carbs may be different, as the bikes are different years and makes, but I'd imagine they would be pretty similar. Thanks!

Hey Mackeil, I have a 1976 XS500C and I think I may be having some similar issues. I just cleaned the carbs out and switched to K&N pod filters instead of the stock filter, and I am experiencing erratic idling (mainly while riding) and occasional engine racing (mainly on startup, when it's still choked). When I reassembled the carburetor I replaced the gaskets, but that was it. Do you think this could be the same issue? I'd like to know how this worked out for you if you were able to get the replacements! Also, which part is the E-clip? I can't quite place it...The carbs may be different, as the bikes are different years and makes, but I'd imagine they would be pretty similar. Thanks!

If you didn't re-jet your carbs after changing to pod filters then that is where your issues are coming from.

If you didn't re-jet your carbs after changing to pod filters then that is where your issues are coming from.

ok thanks, that's what I was thinking, but was unsure how the process worked... been doing some reading and think I'll be looking into re-jetting. Thanks,

http://www.mikesxs.net/products-75.html#products

Part #48-5021

and Part #48-5022

If it does turn out to be this seal, I had the same issue and documented the process here: http://www.yamahaclub.com/forums/topic/14526-1981-yamaha-xs400-special-ii-xs400h/page__view__findpost__p__79825