Motorcycle Repair: not sure, honda shadow vt 750, rotor stator

Question
i have a 1983 honda shadow vt 750 and it wont keep the battery charged i have replaced the brushes in the starter already and it didnt help i have went over the wiring and still nothin can you tell me anything else i might be able to check or fix so it will charge the battery

Answer
Mike, there are three parts to the charging system, the rotor, stator and regulator rectifier.  You can check the stator by checking the resistance between the three yellow wires.  They should all have the same resistance between them and no continuity to ground.  The rotor is the the flywheel with the internal magnets so unless the magnets are weak, it's probably okay.  The last part is regulator/rectifier.  I'm not sure if those can be adequately checked with a simple voltage regulator but if you have checked the other two, it's probably the regulator/ rectifier.  You might also want to check the connector from the stator to the harness.  Sometimes those heat up and start to melt.  If that happens, it will make a poor connection and the battery won't charge.

Regards
Rich