I just put a Yoshimura Comp Full System on my 03 Raptor. I changed the two main jets to 160, and 165. It's not running good at all even when I take the air box lid off. If any one knows how best to set this bike up, please let me know. ie. different jets, air box mods..... Thank you.
I have a 03 raptor with full WB and pro design and a k&N filter with no lid and a dyno jet kit in it running 170 and 175 and the needle on the 3rd clip. I ride below 1500 ft in glamis and it runs great. hope this helps
the biggest problem I found is when rejetting a Raptor , you have to be careful to make sure the vent tube didnt get kinked, thats the one that comes up from between the carbs and makes a loop up and back down at the bottom rear of the gas tank, GOOD LUCK