400ex help needed, backfires and cuts out at full throttle help fast

[drewh716]

My 99 400ex wont rev up in gear, it just cuts out and dies. When it is in neutral or clutch is pulled it revs up then backfires. can anyone help me fix this? please respond or even better just email me at drewh716@aol.com thanks

[nosliw]

quad?
mods?

[2000400EX]

Yeah, we need more info. Just taking a guess...you may be lean on your jetting....just a guesss though.

[416mx]

MAKE SURE THE AIR BOOT IS ON THE BACK OF THE CARB, IF IT FALLS OFF IT WILL DO THAT EVERYTIME!!;)