400ex leaking gas

[SnowFlake]

Sometimes when i run it and let it sit it and idle, it like to POUR gas out of the vent hose. IT runs fine. I took the carb apart and cleaned everything but it still happends. It happends if i dont turn the gas off all the way off after riding. IT has to be at the exact(sp) off position. It would leak all night out of the vent hose. Please dont say its the floats cause i dont know one thing about them.

-pat

[YZ400EX]

It is your float!! Sorry..You are set too low..the float works like this. when gas comes into your carb the float (floats) to close the needle valve when the carb is full of gas. In your case the float is set too low so when your carb fills with gas the float comes to the top, but the setting is set too low so when the float is at its highest level it doesnt close the needle valve all the way. It is a very easy fix..you will see the little aluminum part on the float the sits on the top of the needle valve. just raise it a little. this way when your bowl is full it will close the valve. Just raise it a little because if you raise it too much you wont be able to get enough gas in your bowl and may starve for gas sometimes at WOT. Anyways hopes this helps..It is an easy fix though.

[SnowFlake]

Ill try that thanks for the help.

-pat

[YZ400EX]

Yea just do that..It WILL fix your problem..

[mwmg416]

Mine started to do the same thing this past weekend. I took the carb off and found a small piece of trash in the fuel inlet passage right before the float valve.

[LazeR]

It might not be your float! I broke my clamp that goes on the fuel hose from the tank to the carb...and i ran it, and noticed it didnt leak so i rode around for awhile, let it cool down so i could wash it....then i washed it started it up and it leaked gas out the overflow (it ran perfectly fine but gas flowed out of the overflow) the only way i could get it to stop is shut off my gas! So i couldnt figure it out then i remembered my clamp, so i went and bought a new one, put it on and that solved my problem, i guess it was taking in air or something and causing it to leak gas out the overflow! or maybe it was just coincidence.

[YZ400EX]

Originally posted by LazeR
It might not be your float! I broke my clamp that goes on the fuel hose from the tank to the carb...and i ran it, and noticed it didnt leak so i rode around for awhile, let it cool down so i could wash it....then i washed it started it up and it leaked gas out the overflow (it ran perfectly fine but gas flowed out of the overflow) the only way i could get it to stop is shut off my gas! So i couldnt figure it out then i remembered my clamp, so i went and bought a new one, put it on and that solved my problem, i guess it was taking in air or something and causing it to leak gas out the overflow! or maybe it was just coincidence.

That is impossible for this to happen. More than likely in your case the fuel line was leaking and running down the carb to its lowest point which made it look like it was coming from the overflow, but in fact it was coming from where your fuel line connected to the carb or tank instead (which ever side didnt have the clamp)..Having no clamp on your fuel line would not make fuel come out the overflow..The float controls this. Its the only thing that can cause this unless you had a bad needle valve. Those are the only 2 things.

[SnowFlake]

Ill rip a part the carb tommrow and check for those things.