View Full Version : CB 500 charging problem

05-13-2010, 9:18 PM
Hey chop guys, any help here is mucho appreciated, i'm puttin my '72 Honda 500 four, and I can't quite figure why it ain't charging, I downloaded a wiring diagram from the Internet, and i have a shop manual, I'm almost positive everything is wired right, I've used a meter to check the resistance on the field and stator coils and they ohm out real close to what the manual calls for. With a hot battery it runs great of course, but then if you ride it a little while, she'll just putter out and die, and the battery is dead, I'm not running a daytime headlight, or any other accesories, just a taillight. After it sits for just a little bit the battery will up just enough to start it, but it won't run long, and it sputters like it's not charging. Do I have a drain on my battery or what?? Please help!!!

05-13-2010, 9:55 PM
Regulator / rectifier, replace it and you'll find a world of diference.

05-14-2010, 4:56 AM
I put a reg/rectifier combo on it, it didn't help, i've put the stock unit on it to make sure that wasn't the problem......

05-14-2010, 5:17 AM
If you've got a meter, make sure that when you turn the key on (bike doesn't have to be running) that you get voltage at the field winding. It's gotta be "excited" before it'll charge. Might be a bad connection in a wire somewhere. Did you re-wire it or is it still th stock harness? 30 years of riding/weather/previous owners can wreak hell on wiring.

05-14-2010, 8:31 AM
It's pretty much rewired, but there aren't that many components in the system, are there? I made sure the 3 yellow wires were goin to the right place, and that the white front the field coil was hooked up to the reg/recitifier, and the green from the field coil was grounded. I fed the recifier with a constant hot wire, and the regulator with a keyed hot wire. Am I missing something?? Thanks again for the help guys!!!