Poor idle, leaking out overflow, sputtering

[mbx5]

Does it sould like a stuck float? Poor idling, cracks and sputters, and when I shut the bike down, gas leaks out the overflow until I shut the gas off... It doesnt leak out the overflow when the bike is running...

Any thoughts?

Thanks!

[BigBore24]

yep thats exactly what it sounds like. i went through the exact same thing with mine this past weekend. i did a re-jet and somehow the float stuck in the carb. i didnt understand why it was running bad however until i took the vent tube off that goes into the intake tube and found a puire gas vapor coming out of it due to the excessive amount of gas in the crankcase. this is also how i discovered that my gas petcock doesnt work too well. hopefully if you take the carb off and unstick the float she will seal up fine, then change the oil for sure.

[REPOMAN]

it happens from time to time. tap the float bowl with a rubber mallet and see if it free's it up. or just go ride through a whoop section at your local track and it should free up

[NacsMXer]

Originally posted by mbx5
Does it sould like a stuck float? Poor idling, cracks and sputters, and when I shut the bike down, gas leaks out the overflow until I shut the gas off... It doesnt leak out the overflow when the bike is running...

Any thoughts?

Thanks!

Sounds exactly like a sticky needle valve in the float bowl. The reason it's sputtering is the motor is alternating between getting fuel and not due to the needle valve. Same reason it's leaking out the overflow. Could be a sticking float too, but the needle valve is right under the float so they're kinda intertwined.

My FCR was doing this same thing at the track. I would go out for a couple laps, then it would die in a turn......I look down and it's pissing gas out the overflow. After I cleaned everything with carb cleaner it fixed it for a little but then came right back. I ended up getting a new needle valve and it fixed it right up.

I would try cleaning everything up with carb cleaner/compressed air to begin with.