Carburetor Blowback

[cbrown74339]

Hello,
I have a 400ex that has sat for a while. about a year actually. I have drained the gas, cleaned the carb up a bit and also cleaned the air filter and fuel lines. The bike will start and idle just perfectly. In fact it will idle for 20+ minutes with no hesitation. It runs fairly well except that the carb has an air blowback sound when in gear and driving. This happens rougly about every 10 seconds or so and as you can guess, it very much affects the performance of the bike. any help would be awesome.

Thanks

[2muchquad]

Head gasket.It will probably run fine after it warms up.I have seen that before.Is there any oil on the head on the exhaust side?

[unitednations]

Yah head gasket Mine did that 2

[cbrown74339]

Turns out that something in the throttle mechanism was bent. too it to a local bike shop and they said that the piston in the carb wasn't dropping all the way down. They said it would be easier and cheaper to just get another carb from salvage or somewhere. Found one at a local salvage, replaced, and she runs like a dream now.