ahh sry i did not respond..i did not jet it personally but yes my dealer jetted it when he installed the pipe..u see the pipe was a surprise and when my dad took took my quad to get it serviced the dealer put the jetts in and the new pipe on..but i know thats not the problem because it only has backfired when ive had exhausts leaks..when i broke my first silencer the second i put my new one on i had all the power back and the backfireing stopped instantly! It has only backfired when ive had problems with the exhaust..not once has it backfired w/o there being a problem with the pipe.