Motorcycle Repair: carb overflow, european bikes, suzuki 550

Question
hello,
 I have recently aquired an 81 suzuki 550 E with 4 carbs attached to 4 seperate small air  foam filters .
 The petcock wasn't functioning so  i put on on off valve in the line itself and  gas is reaching the carbs  only now the gas overflows into the filters when I turn the gas valve to on and start up the bike.  I checked to see if the floats were stuck and they are ok. they were shuting off and on fine and I also cleaned the carbs when I first got the bike according to the manuals .  I'm new at this though so if it wasn't put together right before i got it i probably wouldn't notice any small differences.  I don't know ...any suggestions would be great.  

Answer
Hi Vena.
 Well, first of all, you need to replace the fuel valve with the correct one for the bike.  The one that you have is allowing the fuel to gravity feed into the carbs with enough pressure to bypass the float valves.

Fuel valves on Japanese and European bikes work this way;

the valve has 2 lines.  One large for fuel, and one small for vacuum.  The vacuum line is normally connected to one of the intake manifolds, but can vary from bike to bike and depends on if the bike has a fuel pump or not.

When the bike starts up, a vacuum is created in the manifold as it sucks air and fuel from the carb, pulling air from the line going to the valve as well.

 The valve is actually a diaphram that opens from the vacuum, allowing fuel to flow into the carbs.

You will need to get the repair manual to see where everything hooks up on that bike as well as when regular service is to be done and what service is to be done for maintainence, along with all of the specs and repair proceedures for that bike.

Good luck.
FALCON