Hi All,
I'm trying to resurrect a dead petcock from my GSX400.

These things are similar to the GS500 petcock but are built straight into the fuel tank.

I plan on opening it up tonight and seeing what's wrong.I reckon it'll be a busted diaphragm.
I have heard of folk repairing this with a piece of rubber. My question is;
Is there any special type of rubber to use?  :dunno:

Natural rubber degrades in gasoline.  

Viton is popular for fuel-resistant gaskets.  If you have ethanol in your fuel, you may want to stick to Viton, Buna-N, Neoprene, polyethylene, nylon, polypropylene, Nitrile, or Teflon.  Polyurethane and PVC can degrade in ethanol.

There's a discussion about buying Viton in sheets at http://forums.biodieselnow.com/topic.asp?TOPIC_ID=7276

trojan  

Remove the old rubber and parts.. plug the vacuum line (both ends) and ride on prime    Thats what I did :mrgreen: Who needs vacuum lines !

http://gstwins.com/forum/viewtopic.php?t=19363

maybe youll be able to do this??

See my previous post about petrol in my oil.

Fuel has been leaking through the petcock, past the float needles and into the cylinders. There it seeps down into the sump and wrecks the oil.

I figured new float needles might fix it but it'd be good to have a working petcock too.

Thanks for the tips. I used some polyurethane from a thick plastic pocket.
I don't put any ethanol into my fuel, so it should be good.
It seems to be working now, I'll let you all know how things go.