I have a 2005 yfz450 with a slip on performance exhaust and K&N air filter with no air box lid and i wanted to know what to jet it at with a dyno jet jet kit.

 

its really a kind of guessin game ur best bet is to talk to the closed atv shop to u and see what they think and they could take a clos guess to what it needs to be but shouldnt be any higher then a stage one jet i dont know about the yfz but my honda has like a 118 jet stock i would prolly try a 130-140 and see how it run u might have to do a lil ajusting to make it run rich or lean

 

sand man, email me at bigdeala102@yahoo.com, i have the same quad, same jet kit... ? also i have same mods, and i live in oklahoma, so ours are gonna be kinda close i guess...im at 1000 feet above sea level