have a 1982 gl1100 once motor is warm, about half hour of riding, develops misfire on right cylinder bank, #1 and #3. Cleanded carbs, replaced fuel filter, test ride bike, same symptoms. Replaced coils with new coils for a cb750, they bolt right in place and have same wire connections. Now bike is hard to start and runs very poorly, sputters, backfires. Has spark on all four cylinders, but acts like timing is wrong. Timing is none adjustable. Any suggestions???