Motorcycle Repair: CB750 Custom Battery Charging Issues, stator coil, 3 rotor

Question
Hi Bill,
I have a 1980 CB750 Custom with 9500 miles. I have had this bike in the shop about 3 times to deal with the charging system. Every time I get it back, I go for a ride and the battery dies. I know its going to happen when the turn signals are solid, not flashing. I have had the following parts replaced:
1) Stator coil; 2) rectifier; 3) rotor
The battery still will not charge. I went to the NAPA and bought a sealed gel-style battery, and the bike ran fine for about 30 miles, then it died again. There is a slight pop in the # 1 cylinder, and the last time it died it acted peculiar. I turned on one turn signal, it was solid, and then the bike would not accelerate past 4000 RPM. About 300 feet down the road it started to backfire really loud out of the #1 or #2 cylinder (left side) and then died completely.  Could the ignition module be the problem with the popping, and ultimately the charging issue? I feel like I have replaced everything that could be keeping the battery from charging. Any suggestions? Thanks in advance!!

Answer
Peter... Generally, the rotors are the main problem on these bikes, after the generator brushes wearing down.

Go here for comprehensive troubleshooting diagrams...

http://www.electrosport.com/technical-resources/library/diagnosis/fault-finding-...

also: http://www.electrosport.com/technical-resources/library/known-issues/street_4420...

Bill Silver