my buddy has 04 raptor 660r he has fmf pipe slip on kand n air filter. 145 and 150 main jets. he put a high flow alumunium air box on and it is popping and cracking and backing and dies at 3/4 throttle and up. he did not changethe pilot jets. they are still stock. i think that is his problem. what size does he need to go with. the 22.5 is what the ones he has now. thats what it says on the side. is there any thing else he needs to do? i posted in the sticky anbout jetting too.