Bridgestone Motorcycle Parts Discussion Board

General Category => General Discussion => Topic started by: Royal Rick on May 13, 2017, 09:00:10 PM

Title: Need advice on a fuel problem
Post by: Royal Rick on May 13, 2017, 09:00:10 PM

Hi guys,

I picked up a '77 Suzuki GS400. It had a leaking fuel cock, so I bought a rebuild kit and the leak stopped. I got the bike running and everything was fine. I shut off the fuel cock, parked the bike in the garage and the next morning had a huge puddle of gas on the garage floor. Thinking the problem might be the carb bowl gaskets, I removed the bowls (full of gas) and ordered a new set. While waiting for the new gaskets to show up the bike continued to leak gas through the carbs.

I'm thinking this has to be a fuel cock issue but a guy at the Suzuki dealership said it was a carb float problem. I don't understand how the carb is getting gas if the fuel cock is in the off position.

Help!

Thanx so much. I know this is a Bridgestone forum but I can't seem to find a good Suzuki forum and you guys have always been great.

Title: Re: Need advice on a fuel problem
Post by: hardy on May 14, 2017, 01:54:25 AM

I would agree with you, if you shut the fuel off, the only thing Fuel that can leak is what's left in the fuel hose.

You would need to remove the fuel hose and check the tap is still not leaking overnight.

Title: Re: Need advice on a fuel problem
Post by: BRT-GTR on May 14, 2017, 02:52:08 PM

     You have two issues :-

                 The overhauled fuel tap is still allowing fuel to pass to the carbs even when turned off.  Recheck internal seals
                 The carb needle valve(s) are not shutting off, either dirt/gum in the valves, worn needles/seats, puntured float or mechanical issue.

Title: Re: Need advice on a fuel problem
Post by: Royal Rick on May 14, 2017, 04:17:33 PM

Thanks, guys. That makes sense.

Title: Re: Need advice on a fuel problem
Post by: Garry Haliburton on May 14, 2017, 09:18:43 PM

Royal Rick, I had a 1977 GS750 it had a I believe to have a vacuum controlled fuel shut off. Didn't have to turn it off and on. No fuel gauge, but must of had a reserve can't remember. Is your GS400 like that? If not then the fuel cock should shut  off the gas to the carbs if working properly. Hop

Title: Re: Need advice on a fuel problem
Post by: dcr on May 15, 2017, 11:01:44 AM

Pull the fuel line that runs from the fuel tap to the carb off the carb and with the petcock off, see if fuel is coming out of the fuel line. Put a bucket or other container under it and let it sit the night. If you come back in the morning and there is fuel in the container, you have your culprit.

Dan