Motorcycle Repair: 1998 Sportster, harley davidson 883 sportster, harley davidson 883

Question
Hi Mike,
1998 Harley Davidson 883 Sportster 15,500 miles.
Screaming Eagle jet kit W/K&N air filter installed at 1000 miles.
1200 conversion kit install at 10, 00 miles.

Problem:
Bike will sometimes not start, engine will turn over, and backfire, but not start.  After a waiting period of anywhere from 10 minuets to overnight with the ignition turn off the bike will crank right off.  In all operating throttle positions motor will intermittently cut out or misfire causing a momentary hesitation.  
On at least two occasions after traveling 50 to 70 miles or more at highway speed the motor will just quit, symptoms seem to be loss of ignition,  with continuous backfiring, but electrical power remains (head lights are unaffected and no engine lights ect) this continues with the cutting out with stopping/starting for a mile or more, and then the engine begins to operate normally, with the intermittent hesitation continuing.

Action Taken:
Drained and replaced gas.
Verified gas gap venting properly.
Replaced the main circuit breaker.
Tighten loose battery ground (discover loose when changing circuit breaker).  

Answer
You either have a short or a ignition that is going bad. When trying to start the bike and it doesnt start pull a spark plug and test to see if you are getting a spark by holding it to the head and cranking the motor. Just to see safe, I would test the coil also, but usually coils dont break up like that. If you need to know how to test the coil let me know. You will need a OHM meter for the test.
Let me know what you find
Mike