This is probably going to seem like a ridiculous question...

There are two lines that come off the petcock. One goes to the fuel filter and then the fuel pump and the other one goes to... Where? I just purchased the bike and the second line coming off the petcock was disconnected when I bought it. The manual is no help.

 

I'm not specifically familiar with the VF500, but my VTR1000 petcock has a vacuum shut-off so the fuel can't flow with the engine off. A small vacuum line from the petcock connects to a port tapped into the the side of one of the engine air inlets, between the carb and the cylinder head. The vacuum signal moves a diaphragm in the petcock that opens a valve to let the fuel flow. These are a source of problems on older bikes as the diaphragm can tear or the valve stick shut, but they are easy enough to fix with new parts.

 

make sure the extra hose is plugged with a screw, bolt, or something or it may be leaking air into one cylinder and causing running problems.

 

Your hint gave me enough info to find where the vacuum line was supposed to go. the opening had been filled with a phillips head screw with the appropriate thread, so it was camouflaged as just another set or adjustment screw on the carb. Thanks for the help!

 

Glad that helped, Spoons


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