Motorcycle Repair: 1985 Yamaha Virago 1000cc, combustion chamber, fuel mixture

Question
When traveling the engine is missing and backfiring and there is somewhat a gas smell.  Could this be from not letting the bike warm up that long or something else?

Answer
Brain,
 Sounds like a tune up is in order.  First, check your ignition timing.  Second, check your plugs, replace if neccesary.  Third, be sure your carburators are properly adjusted and all air and fuel ways are clean.  Preignition can contribute to misfiring as well.  This is what happens when the fuel mixture lights prematurely from an overly hot cylinder or glowing ember of carbon in the combustion chamber.  Be sure cooling is sufficient and that your timing is correct.  Number one source of backfiring is incorrect timing.

Hope this helps,
Mike