81 Honda CB 750 Custom Persistent Charging Issues- HELP!!

[Klackey]

This is a pristine bike which had only 6,700 miles on it 3 years ago. It is beautiful and runs so well. But…….We have changed, multiple times, the stator, rotor, regulator/rectifier, battery and still are having issues with maintaining the battery charge at high 12 to low 14 volts after riding for 25 plus minutes. It will die after that and not restart without a new charge. We recently bought all the same brands from the same company/distributor to have consistency across the parts. The wire harness has all wires with no issues when isolating each and seeing if there are any shorts. We have boiled it down to what looks like when it gets warm at about 25-30 miles, is when this situation is happening. I have some of the best working on this, and they are perplexed. They refuse to give up because this bike is in almost new condition. Still has the original stickers. Any thoughts? I’m missing yet another summer of riding this gem, and I am discouraged. It is my dream bike. Thanks.

Kelly

 

[brettp]

This could become a lengthy discussion, and people are going to ask you some very basic questions so have some patience. Here is a couple questions to get things started.
Are all the electrical connections clean and free of corrosion, from the stator wires all the way to the battery?
Is the battery ground at the frame clean?
Are any of the three yellow stator wires grounding out?
Are you getting AC voltage out of any of the three yellow wires on the stator with the bike running?

 

[Klackey]

This could become a lengthy discussion, and people are going to ask you some very basic questions so have some patience. Here is a couple questions to get things started.
Are all the electrical connections clean and free of corrosion, from the stator wires all the way to the battery?
Is the battery ground at the frame clean?
Are any of the three yellow stator wires grounding out?
Are you getting AC voltage out of any of the three yellow wires on the stator with the bike running?

Thank you. I have copied and sent your reply to my friend who is the one working in this for me. He and a couple other friends are the experts. I’m just learning from them. Thanks again for the super fast reply!

 

[Loose Chain]

I would suggest mounting a temporary volt meter up near your instruments where you can see it as you are riding, and see when things start to change. Make sure it is charging when you leave and see when and where it changes. You can determine if it is heat related or set off when going over a bump and that sort of thing. As Brett pointed out it might come down to a bad connection.

 

[Klackey]

I would suggest mounting a temporary volt meter up near your instruments where you can see it as you are riding, and see when things start to change. Make sure it is charging when you leave and see when and where it changes. You can determine if it is heat related or set off when going over a bump and that sort of thing. As Brett pointed out it might come down to a bad connection.

Thanks. I got one last week and will take to my friend to out on. I sen him your first post and he said he liked your thought process and it gave him some ideas to try tomorrow. I’ll pass this along too. I’ll let you know. Thanks again!

 

[mrtwowheel]

{ recently got two '81 CB750C's running, both had no charging problems before. Both had charging problems this time around. One had a bad wire to the regulator. One had a connector pin barely pushed out of it's plastic connector block. Just some things that can possibly happen. Yeah, an onboard volt meter is a good thing to have.

 

[Klackey]

Thanks guys! We’ve got some good things here to consider here. I’ll get back to you once my friends get back to work on it. I appreciate the help!