My air box was leaking gas, so I figured my carbs were overflowing and leaking into the air box. I took the carbs out and cleaned them, the float needle was in good condition. I put everything back together and ran the bike again. Gas started leaking from the air box again, and now the bike idles at 5000 rpm.

I think I may have tightened the throttle cable too much, do I have the disassemble the bike again to reach the throttle cable on the carbs or can I adjust the cable at the handle bar? (It's my first time working on a bike)

As far as the leaking gas, any other ideas? I read some other posts saying that if the fuel valve was on "prime", that would cause the carbs to overflow.

Thanks, can't wait to ride again.

Are your hoses routed correctly?  See here:  http://wiki.gstwins.com/index.php?n=Main.HoseRouting

My bet is float height or needle seats.  If your petcock is on PIRme, turn to ON.

Float height check: http://wiki.gstwins.com/index.php?n=Maintenance.FloatHeight  That's the official way.  Another way is the 'u' tubing float height check seen here:  http://www.bbburma.net/FloatHeight.htm

Good luck!

Correct on gas leaking with stuck, dirty or out of adjustment floats. They are what stops gas from flowing to the carbs. If they are bad, carbs will overflow.

PRIME will let the carbs overflow with the bike off if the floats have problems. If the floats are OK, it will not flood.

ON and RES with the bike running lets fuel freely flow. If the floats are bad, you'll run very rich because they are not stopping gas from going in and the casrbs will overflow while running. You won't see much extra gas in the airbox because it is being sucked in and blown out of the exhaust.

Ok thanks, that's good to know about "prime", "res", and "on".

Do you think replacing the floats would fix the problem? I have no experience with carbs, so I don't have a baseline for what is normal.

I drained the carbs and started the bike in the "on" position. It worked fine then started overflowing from the air box drain again and stalled. I drained the carbs again and restarted the bike on "res" and the same thing happened.

Buy a shop manual.

Use the search feature of this forum.  You'll learn a lot, and most of the time, there are pictures.  Also check wiki.gstwins.com

If your float needles and seats are dirty/worn this will happen.  If your float height is improper, this will happen. 

If it's the float needles, only buy OEM...don't buy aftermarket.

The float height is set by bending the tab on the float to achieve the height specified in the link above. 

It can be intimidating to work on carbs and bikes at first (Ask me how I know this... ), but take your time, and with a good shop manual and this forum, you'll be surprised what you can do.

For instance, I just did my first carb sync based on pictures and instructions from this forum coupled with my Haynes manual.  Both are worth their weight in gold!

When the bike is running, ON and RES are the same as PRIME. That is, gas is freely flowing. When running in ON or RES, the vacuum from the carbs opens up the fuel valve, same as in PRIME (which lets fuel flow in the absence of a vacuum).

The floats/needles in the carbs are what stops the fuel flow. They control it so the carbs do not overfill and flood. When they don't work (stuck, dirty or adjusted wrong) things flood.

I will try adjusting the float then. Will it damage the carb if I test it with water before reinstalling everything in the motorcycle? I'm thinking I might flow water down the inlet and see if it leaks out of the overflow. I've attached videos of the carb in question





Thanks for the help, glad I found this forum it's a good resource. I bought a clyder shop manual which is also proving helpful.

You can just use gas for the test, water is not good for carbs 

Agreed.  Just stick a small funnel in the main fuel intake line, and test that way.  No leak and you are good.  You'll need 1/2 gallon of gas.  Take the rest and either use it for your ride, or your cage.

Just hook the tank lines up without having the carbs installed on the bike

I adjusted the float needle and tested the carbs, they're working ok now. I put the carbs back on the bike and started it without the air box. It ran ok for a while but it started spurting MASSIVE amount of liquid out of the top of the engine via somekind of breather hose. Not really sure what is going on now...

Check your oil. Sounds like it got loaded with gas and now your crankcase is full of oil/gas mixture.

Probably need an oil change.

Dip stick probably shows WAY over full.