Help jetting my 85 250r

[tbus93]

Hi I need some help on the jetting for my 85 atc 250r will be running the esr 310 kit with a port job from f.a.s.t racing boysen rad valve 39mm pwk carburetor K&N eliminator kit running a Paul Turner high rev pipe running 110 Blue VP racing fuel at 925 feet above sea level help?? please help I have no clue on how to Jet

[yaegerb]

IMO, I would start with a 55 pilot and a 180 main with the clip on the needle 3rd from the top. Remember your jetting circuits are on throttle position and are the following: 0-1/4=pilot, 1/4-3/4=Needle and 3/4-WOT = Main. Only adjust one circuit at a time and plug chops are your friend.

Another item to note to fine tune your pilot jet. Your airscrew needs to be between 1 to 2-1/2 turns and should have crisp throttle response. If your throttle response is crisp below 1 turn then your pilot is to small. If your throttle response is crisp above 2-1/2 turns then your pilot is too fat.

That should get you started

[tbus93]

thanks yaegerb for the advice