QuestionHey! You probably get this one all of the time, but I have a 1980 CB650 Custom and here's the deal. When I bought it I assumed the battery was dead so I used a car battery to fire it up. When I disconnected the spare battery the bike died, same thing when I leave the bike running with the other battery on it for a bit It doesn't seem to want to hold a charge. Shouldn't the stator/alternator run the bike sans battery? If i disconnect the stator and run the bike off of another battery, should the stator produce a reading on my meter regardless and if it doesn't does this mean it's dead? Any info would be super, thanks. Johnny T.
AnswerJohn, the bikes are battery powered, so disconnecting the battery from the circuit kills the voltage to the ignition system. There is no place to store voltage and amps with no battery in the bike. The charging system monitors system voltage and responds accordingly within a specific range. The ignition components need to see over 11 volts to function properly.
Go here for troubleshooting details:
http://www.electrosport.com/technical-resources/library/diagnosis/fault-finding-... They offer replacement parts at far below Honda OEM pricing.
CB650s have a history of faulty alternator rotors, which can lead to a melt down of the regulator rectifiers. Also check the stator lead to the harness for overheating or corrosion at the connector.
You have to look at all the components in the bike... stator, reg-rectifier, carbon brush condition and connection to the rotor.
Do NOT do troubleshooting with a dead or dying battery! Use a fully charged, fresh battery to do your tests.
Bill Silver
