Motorcycle Repair: 1986 Honda 250ES Big Red 3 wheeler, honda motorcycle, vacuum hose

Question
Took apart the carb cleaned it...put it back on..now it will only run with the choke on full. When you let off on it, it backfires.

Answer
Tim, it sounds like perhaps you flushed some dirty fuel back into the carburetor after the clean-out and it plugged up the idle jet.

http://www.bikebandit.com/houseofmotorcycles/1986-honda-motorcycle-atc250es/o/m1...  
CARBURETOR for illustrations of the parts and the vacuum hose assembly. All hoses need to be assembled correctly. Idle jet is only #38, so easily clogged. Plugged idle jets are the usual source of no-idle, backfiring.

I would double check your valve clearances, if they haven't been checked for awhile. Often overlooked and the clearance is so small that it doesn't take much of a change to hold valves open, reducing compression.

Bill Silver