350 raptor backfiring

[headache]

hey guys i just traded for an 05 350 raptor. only mods are baffle removed from pipe and k&n air filter. It starts and runs great and even accerates good, but when you let off gas completely after revving motor up good going down a trail, it has a loud backfire come out the exhaust. almost sounds like a shotgun going off. Only does it once at a time, i've heard quad have lots of small popping coming out of pipe b4 this isn't like that. It doesn't seem to have an exhaust leak or anything. Could the pilot jet be too lean cause this? i pulled the sparkplug and it looked kinda black. gonna put in a fresh one and see what color it turns after a high speed run. any help would be appreciated

 

[88WarriorBoy]

Yeah pilot jet but they can still back fire with the right jetting because the carb dumps in fuel at wide open then you let of and that excess fuel has to go somewhere lol

 

['00 WO-YA!]

Getting the pilot right will cure 95% of the problem. I think that is a BSR carb and if it's like the one on the Z400 you'll have to remove the stupid plug that keeps it from being tampered with. Do that and adjust it out and see if it gets better.

 

[88WarriorBoy]

yeah the rappy carbs are BSR

 

[headache]

ok thanks guys. i'll try that and see what happens!