Troubleshooting Unique Charging

[Tracer]

I need some basic troubleshooting instruction. Technically, this for my Honda CB900C I'm selling. But I'm selling it to cover the GS1000GL I just bought, as well as some costs of getting it up to snuff. Plus, this problem has been stumping me since I've had the bike, and I think I'm pretty close now, so I'm calling on all the help I can muster.

The bike charges fine--up to 14.5VDC--as long as I remove two fuses. One fuse goes directly to the headlight, and the other goes to the running and instrument lights. With these fuses installed with all the others, I can hardly get the bike to charge above 13VDC, and then it takes a long time with the throttle set for 4K RPM.

Some additional info.: The stator and rotor have been replaced with rebuilt, and I've tried three other R/Rs and have gotten the same result.

I'm open to any troubleshooting suggestions and techniques, as I'm not too talented there. I've mostly been just pulling things, like fuses and bulbs, to see if there's a change in the charging rate.

Are there other tests I can do with my multimeter to better isolate, and then correct the problem?

Thanks in advance.

[ESMarcus]

Have you taken a look at the brushes? It sounds like they could be the problem with your low charging. That and have you gone through any of your wiring to make sure that all the connections are clean? I have seen quite a few bikes where the charging wasn't improving after replacing parts, and fixing a bad connection bumped the charging up to where it should be. If it ends up being the brushes I would contact Stockers Starters and talk to Elwood like the blues brother.

-Marcus
Electrosport Industries

[Guest]

Sounds like a bad stator. It can't handle any load such as the headlight.

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After I shut the PC down last night and kept mulling the problem over, I began to wonder if the problem was back in the alternator, and that it was just not capable of powering the lights.

I'm going to work through the Stator Papers' procedures to see what I get. Looking over them, I've actually done a lot of it already, but I can't locate all the notes I took

I did replace the brushes, actually. I just forgot to mention it. Here are some of the other things I've done:

I did an AMPS test on the rotor, and it passed very well.

I did the VAC tests on the yellow wires coming from the stator, and I think I got something around 25-30VAC across the board. I'm not sure if this is within specs since my CLYMER manual didn't offer that data. I know that the Stator Pages indicate that the GS line should put out about 60VAC. If the Honda alternators are supposed to me close to that, then the problem may be there. I've got a CB900 online group (that is pretty minor compared to TheGSResourses) that may have someone who knows.

I can't say that I've gone through the connectors as closely as I should have, so I'll do that too.

COncerning the connectors, is this primarily for the connectors within the charging system? Or through the whole harness?

Thanks for the responses, and I hope to have some more to report over the next few days!

[Tracer]

The issue is now moot. The CB900 sold yesterday, and now someone else owns it. I charged the battery the night before, and when I fired up the bike, it showed no sign of charging problems. Unreal. I'm sure it was because I was up front with the buyer about the charging problem to begin with. I guess I'd rather have that egg on my face than the reverse.

Thanks for everyone's replies. From here on out, it's only the GS1000.

Thanks.