Motorcycle Repair: Bike Problem, street bikes, valve adjustment

Question
Chris,
    This involves a four wheeler problem. I have adjusted the valves on a 2002 300ex. But before that the bike when I start it it backfires and pops the carb off. It did it before and after the valve adjustment.This the first problem I have had with this bike.  

Answer
Hi D.
 If the valves are set correctly and the ignition timing are correct, then this should not be happening.  Double-check your valve timing and make sure that it was set to the correct position on the timing wheel.  It is also possible that the valves are set slightly reversed for intake and exhaust.  Since it's not a multiple carb bike, then there is no synchro problem, which would be a factor in this on most all street bikes.

Go over it again and see what you get.  Double-check what you have against what the manual shows and you may find that it is just slightly off.

Good luck.
FALCON