I have installed and modded based on all the recommendations here; bought a needle JD and think its 4th position, fuel adjustment screw(about 1 3/4 out), new main (think its a 165) opened the airbox, have a 450R silencer on it. Has the block off kit installed. Once warm it runs good but I think it might need more fuel around mid way and when on the gas and rapid off lots o popping and you can see some fire on a video clip I had.
Suggestions on what to try next????