Ok ive tried to do as much trouble shooting as I can, but im beyond my level of ability. The bike will crank and run most of the time….it sounds like it has a slight miss at idle but nothing that raises by brow. When the bike is cold it runs and accelerates GREAT! When it gets warm to run good on the low end and top end RPM but if I have it as a medium RPM and nail it, it back fires and stutters until the RPM raises. When I stop the bike and let it idle for approx 20 secs and get back on it after idling it runs great for another 20 seconds or so then back to spitting and backfiring. When at an idle and warm I can turn the choke completely on and it doesnt affect the RPM at all. Anyone have any idea where I can go from here.

2008 400ex hot cams gull exhaust KN filter without lid on box air screw 3.5 turns out.

Ok ive tried to do as much trouble shooting as I can, but im beyond my level of ability. The bike will crank and run most of the time….it sounds like it has a slight miss at idle but nothing that raises by brow. When the bike is cold it runs and accelerates GREAT! When it gets warm to run good on the low end and top end RPM but if I have it as a medium RPM and nail it, it back fires and stutters until the RPM raises. When I stop the bike and let it idle for approx 20 secs and get back on it after idling it runs great for another 20 seconds or so then back to spitting and backfiring. When at an idle and warm I can turn the choke completely on and it doesnt affect the RPM at all. Anyone have any idea where I can go from here.

2008 400ex hot cams gull exhaust KN filter without lid on box air screw 3.5 turns out.