1997 Harley Davibson ultra classic Problem is engine light is on and motor is not running but on one cylinder What could be problem?

Not knowing what you have done yet, may I suggest you first check to make sure you have spark to both barrels. If you don't and know your spark plugs are good, then I would run a check on the voltage regulator to determine that works fine. If all is good, I would then check to make sure my coil(s) are working. I would also run a check on my spark plug wires. Did this problem just start up all of a sudden or have you been having intermediate problems with it in the past? Also, I would check to make sure my ignition system was working correctly, and if my timing was set correctly. Hope this helps you.