[Rick2017]

2002 Honda FourTrax 400 running on 110 octane fuel would like for it to be able to go back to stock jets theway it runs now is rough does anybody have any ideas tips and help

 

[retro]

Is this a 400EX or a TRX400? Need more info... a detailed list of mods on the motor and bike is necessary. Compression ratio and Camshaft info, head rework, etc? Unless it was being set up to run on Methanol (or the builder screwed up on choice of camshaft grind), 110 octane racing fuel is not required. Also need to know about the exhaust system and the carb & airbox that is on it. Everything you can tell us about it in detail.

 

[misterclean59]

It the only thing that changed was the fuel then it is running too rich. Usually just one size on the main jet. The slow/pilot jet should be able to be adjust with the fuel screw.