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Leaky diaphragm cover
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I've just completed a carb rebuild (with All Balls kit) but now have a leak from the diaphragm cover. I'm trying to avoid the expense of a new diaphragm so wondered if it also acts as a gasket, sealing against the cover? If it doesn't act as a gasket, then I assume replacing it isn't going to help. I've attached a picture - does it look bit shagged anyway? It was working OK but it had stuck to the float housing, so I decided against peeling it off in case it got damaged. Any thoughts appreciated! Cheers, DelBoy.

 



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The cover plate is also prone to corrosion and pitting - use some emery paper on a flat surface and rub the plate on it to "skim" the surface down to a clean level.
Were new o rings in the kit? Old ones go hard and stop sealing.
The outer edge of the diaphragm is ridged and acts as a seal, but it is usually the o rings and pitted corroded cover plate that are the problem. There is a bit of a crease in your diaphragm, but it's difficult to tell if it is perforated. If it was pumping a decent jet of fuel into the intake it was probably ok.
Good luck!


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OK - thanks for the pointers! The O rings are new and the diaphragm was pumping fuel. I'll give the cover plate a clean up as you suggest and give it one more try ...

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Despite my best efforts, was forced to get a new diaphragm - which when looking at the 'before' and 'after' was pretty inevitable.

Bike is a US import (I believe). When I bought it last year, it had the restrictor plate sawn off the end of the header pipe, snorkel removed and some holes drilled in the top of the airbox. Jets were standard 137 and 50. The bike pulled well in mid-range but didn't idle well and was reluctant to rev out. I dabbled with some bigger jets but never got it to run cleanly across the range, so went for the rebuild and took it back to standard, so snorkel back in, holes taped over and back to 137 / 50 jets. Also found the brass check valve that sits under the float bowl gasket was missing, so new one fitted.

Anyway - after a brief test ride, all seems good - no leaks and no hiccups, so hopefully job done!

Many thanks to those responsible for the rebuild guides on this forum - a massive help!



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Super Guru

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Good news!
A painful expense, but sometimes necessary, and now you have a properly functioning bike again.
Enjoy

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You are right about these guys - they have been a big help to me in the past.



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