need help

[Yfz david]

Ok ive got a factory banshee the only mod is is 0.50 over with weisco pistons ive been trying to tune this thing i cleaned the carbs all the jets are factory ive got the air screws 2 3/4 turns out and the plugs are still white they both have a brown line on the plugs if that makes sence kind of line a burn mark im running the ngk br7es it bogs on take off and on the low end the mid and top end is great revs out cant really get on it fresh top end and i really dont want to toast this thing because of it being too lean any ideas if should i jet it or what i should check if so what size im in east texas and like i said before its all factory any input would be great thanks in advance

[98_shee]

Put br8es in it, air screw should be around 1 1/2 turns out. A stock banshee should be 220 main 25 pilot. If your plugs are white put a bigger main in it.