Motorcycle Repair: backfire, honda gl 650, mechanical portion

Question
i have a 1983 honda gl 650 interstate motorcycle,it runs good on the flats but going down hill it will backfire and every once in awhile will make a poping sound that sounds like ,it's spitting out fire. could the choke not be working right,or is it in the carburators?

Answer
Hi Fred.
 When was the last time you had the valves checked.  Backfiring is not a function of the carbs, but of the vale and ignition timing.

 My guess is that the valve and ignition timing is slightly off.  It's not really anything to be concerned about right now, but keep an eye on it.  If it happens at any other time, get it taken care of.

 Also, if you run downhill with the engine slowing you down, that will also cause the bike to backfire by forcing the timing to retard at a slightly different rate than the mechanical portion of the system.

Good luck.
FALCON