i just put a white brothers slip on pipe on my raptor and now it cuts out on the mid range. when it cuts out you have to be on the throttle about a quarter to half and punch it and it pops and backfires like crazy. this is with 12 discs and no jetting yet. i tried 7 discs and no change but a loss of power. any help is appreciated

 

You are going to have to jet up. you are running way to lean. i am guessing going to a 145-150 or maybe 150-155. thats what i had my pipe jetted at.

 

160,155 mains
27.5 pilot
cut the flaps out of snorkel

 

IF its quarter throttle to 3/4 & backfires you need to move your needle up a notch your to lean

 

what size jets would i need for stock filter.
150, 155
160, 165

or both sets. the funny thing is my plug is light brown. i don't get it. i put a pro-meg kit on my 400 ex and had no problems.(yet).
thanks again

 

redyam350,
do i still need to rejet or just move the needles up. to do that you move the clips down right. the first day i put the exhaust on it ran fine and then it got really cold and started acting up.

 

ok i moved the needles up one position and the bike runs alot better. better overall throttle responce. but do both carbs have the little springs on the needle and two spacers at top,one silver and one brass. if so i must have lost them. should i get new ones or not worry about it.