My buddy has a 450 and put a KN airfilter on it, withno lid, and we were not sure what size jetting we should use. The motor is stock and exhuast is also.

We are at sea level and temp avg 35-55 winter and summer. ANy suggestions would be great.
Thanks.

 

Try a 170mj, 45pilot, needle 4th position, 2 turns out on fuel screw, and go from their.