size?

[exrider12]

alright i have a 250ex with a uni airfilter and an hmf full exhaust and im aat 1000-1200 ft above sea level. what size jet should i put in?i have the dynojet jet kit in it with a 96 main and i get a good amount of popping on decel and my header is blue. so what size?

p.s need to know asap

[ZeroLogic]

Well, what color is your plug? Did you put the sliencer core in? I believe backfiring is from being lean but I may be worng. Its been a while.