Looking for advice on the right Main Jet and Pilot jet to use on my 400 with exhaust, Air Filter and air box lid removed. Its running lean, I Made the mistake of letting the shop put my pipe on and I dont know what or if they did anything to my carb so I dont really have anything to go off of? We mostly ride around sea level. Any advice would be great?

 

If its running lean, take your carb off and find out what jets you have in there, go bigger, until it runs ruch, then back of one jet. Probably only the main will require any changes.

 

Really it depends on what kind of pipe you instaled on your atv.I'm getting a HMF powder coat full pipe kit for my 04' KFX400 and it says you need to go up to a 175 main jet.All pipes are different though...