Buterfly seals

[planedick]

I have finally found seals for the butterfly shaft that I can use for these carbs. They're not the original, but close enough that small modifications to the OD allows a real good fit and seal. Now that I have these and the special tools I've developed for things like removing broken needle tips, and drills and pins for fixing broken posts, I feel I can rebuild carbs for others. Additionally I'm looking for non rebuildable carbs for parts to replace some of those missing on others. If you want/need any of these services, just PM me.

[81xsproject]

It doesn't sound like you will be sharing your new seals tip, eh?

[planedick]

Sure

The seals I found are the real type with the metal inside the rubber, but they are about 0.020" too big on the OD, so I use a special tool I developed to remove some material from the OD until they fit and press them in with yamabond on the outside. The old seals were just rubber and still fit the shaft OK, but they had shrunk and were loose on the OD so bad that there was a large gap. I also found that the butterfly screws will unscrew without cutting anything off the back and will go back in so I can upset the back again to keep them in.

Harwal seals. Lip type: AO, Material: NBR, ID-08, OD-12, Width-03

What you need is a special tool for turning the OD down to the right diameter. This is the part where I don't share.....

[81xsproject]

So, the two options I see from their site are nitrile and viton. I am guessing nbr is nitrile. Why not Viton?

[planedick]

Supplier

I told them it was for gasoline and that is what I got.

[natemoen]

Nitrile degrades with carb cleaners (even the spray can kind). I would have went with Viton, more expensive but you would be pretty dumb to put something in your engine that would degrade viton.

[planedick]

Darn

Just when I thought I was ready to rebuild my carbs to like new I run into another problem. The "T's" for the fuel lines are way to small for the carb holes. I can't imagine fuel not leaking there. It weems like there was some kind of rubber material around them, but it came off when I took them apart. Any ideas?

[bikerphil]

New brass ones, $19 ea, was posted by Marty (I think) in another thread....

http://www.siriusconinc.com/search_r...earch&start=25

[planedick]

Found a way

To fix the "T's" so they don't leak. The original ones didn't leak when I took the carbs apart, but it appears that there was some kind of yamabond type stuff in there and they now don't fit anywheres near tight enough to stop the gas from just flowing out. I found that shrink tube cut just slightly shorter than the distance between the two raised portions of the "T's" and shrunk there is just the right size to fit tightly. It's tight enough even that grease is needed to get them into the carb body. Before I did this I took a peice of the shrink tube and suspended it in the gas tank under gas overnight and it didn't effect the tube at all so I decided gasoline won't hurt it.

[jetmechmarty]

My opinion is that it's too much a PITA to go back and fix the leaky "T" later if the shortcut fix doesn't work. I went with the new ones and rest easy.

I admire the heat shrink fix in a pinch, but it wouldn't do for me.

[79XS11F]

I did mine by using fuel injection O rings. I took the T with me to the auto supply shop and got O rings that are thin and a tight fit over the Ts ends. I put one on each side and placed it between the factory ridges of that rubber coating. Worked great, no leaks, no problems.
Rob

[bikerphil]

My opinion is that it's too much a PITA to go back and fix the leaky "T" later if the shortcut fix doesn't work.

I agree, 100%

[81xsproject]

To fix the "T's" so they don't leak. The original ones didn't leak when I took the carbs apart, but it appears that there was some kind of yamabond type stuff in there and they now don't fit anywheres near tight enough to stop the gas from just flowing out. I found that shrink tube cut just slightly shorter than the distance between the two raised portions of the "T's" and shrunk there is just the right size to fit tightly. It's tight enough even that grease is needed to get them into the carb body. Before I did this I took a peice of the shrink tube and suspended it in the gas tank under gas overnight and it didn't effect the tube at all so I decided gasoline won't hurt it.

IIRC, shrink tube is PVC and PVC is degraded by gasoline. Might want to research further before reinstalling.