400EX not runnin right...

[400EXdude]

its really wierd....it will run fine for like an hour er sumetin....and then it just starts to cut out....like at first you cant even go past half throttle in any gear....and then it will just not run at all..it will idle fine...and then once i pull in the clutch and let it out and give it some gas...it just dies....whats my problem?

keep in mind its an 04....and that its winter but its been pretty warm all the snows meltin....and the only performance upgrade is a white brothers e-series slip on

[throwinitup]

check your jetting you should be around a low to mid 150's MJ with a 40 Pilot....anyone else correct me if im wrong

[khen]

I would first try swapping out your spark plug. If it's been sitting a while you might have some build up in your carb that's finding it's way into the jets. If the plug doesn't fix it, pull off your float bowl and clean out your jets and bowl.

[400EXdude]

well me n dad checked it out....and the spark plug had something done to it....so we fixed that and im pretty sure the valves need re-ajustted...so hes takin it in on monday....and im pretty sure im gonna give him some money to get a jet kit and let the dealership put it in...