I have a 94 cbr 600 f2, I am have a fuel issue. I can not get any fuel out of the tank. I have change the petcock twice and getting the same result. I connect a small container with fuel to the bike and it ran fine. so can I bypass the diaphragm. will the bike run okay without it? please advise.

 

Do you have the vaccum hose from the #1 cylinder hooked up to the petcock?

 

With the tank removed, which I did, and plenty of fuel in the tank. Turn the valve to "on" or "reserve". Put small hose on the petcock vacuum port and start sucking. Fuel should come out of the petcock, not in your mouth but out of the fuel port. I propped my tank on a work bench to replicate the position of being on the bike, with a cup under the petcock to catch the fuel coming out of the petcock. That told me my petcock diaphram was good.

 

I did that and gas did come out as you stated. bike will not start and I guess I will do a complete tune up. do not know anything else I can do.

 

If you hooked up a small container of fuel and the bike started. Then a tuneup isn't going to fix anything. You've still got some kind of problem that needs to be figured out.

If you did Coalminer's test and got fuel. Try hooking everything back up, then take the vaccum off the #1 cylinder and suck on it a bit. this will help get fuel to fill the line below the petcock and fill the carbs. Then hook it's back to the #1 cylinder port. And finally try starting the bike again.

Those petcocks are known to go back every once in a while. When you changed it, did you use a used one? Maybe try a new petcock set from Honda.

 

Also if you've got something like a mity-vac, you can hook it up to the petcock and check to make sure it's holding vaccum and not leaking.

 

I spent a little more time working on it and finally got it to start from tank. everything is well, suck on the vacuum and played with the spark plugs and did some adjusting on the chock, do not know why but after all that and some, it finally started. so thanks,

 

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Umm, that is not the petcock vacuum port diaphragm, that is the carburettor vacuum slide diaphragm.