generator issues

[zman]

Let me start off by declaring that I am electrically challanged. I can install a battery confidently, but anything else, I need simplified instructions. Last week my battery went dead on my '50 Pan. I replaced the 12v battery and that one went low after a few days. The meter read 10.4 vdc across the battery. I R&R'd the solidstate voltage regulator and with the motor running and reving off idle the battery still read 10.4. Down at the bike shop they said to check the generator output with the motor running. So I again started the bike and reved up the motor. I put the red probe on the "A" post and the black probe on the "F" post. the reading was 8.5. What does that result mean? Can I get away with replacing brushes or do I need another generator? Does anyone know of a motorcycle generator exchange or a shop that rebuilds generators? And another question. At the bike shop I was told that I didn't need to polarize the generator because I am running a solidstate regulator.

[steinauge]

To conduct a generator output test; 1-remove the regulator leads 2-make up a piece of about 16 gauge wire 2 feet long with an alligator clip on each end 3-start the engine,run at a fast idle 4-connect your voltmeter red lead to the A terminal on the generator,ground the black lead 5-connect one end of your alligator clip wire to the F terminal on the generator,ground the other end.If the generator is working it will read 20-40 volts DC.DO NOT leave field grounded for more than 3or 4 seconds.If the generator is working you have a regulator,regulator ground or wiring problem,if not-well thats kind of obvious HTH By the way-NEVER attempt to polarize an electronic regulator! If you do all the magic smoke will come out-------

[zman]

Thanks Steinauge for keeping it simple. I followed your instructions and then the bike wouldn't start. (Which is odd since that usually only happens when I have people watching.) I came back the next morning and the bike kicked right over. I pulled the check and the meter reading was 25 volts. That proves that the generator is putting out. And I have a new battery. So the regulator is probably the culprit. I'm going to go to the bike shop Monday for one.

[NightShift]

I think I would use an ammeter instead, and hope for ten or twelve.

Like th' booke.

Respectful,

NightShift

[zman]

Went down to the bike shop for another regulator. Slapped it in and went for a putt. Before I left I put a meter across the battery which read 12.2vdc. After I got back the battery read 10.4vdc. I guess I'm back where I started.

[steinauge]

Always carefully check your regulator ground and wiring before buying any new parts.All the grounded field output test tells you is that the generator works.I dont know what you are using for a regulator,but a lot of electronic regulators are powder coated and unless you scrape the powder coat off the mounting lugs they wont work.

[zman]

OK Nightshift, I set up the test again as Steinauge outlined and I tested amps with my meter and I got 25. Is that in range or did I do the test wrong? I am running the chromed (not painted) solidstate electronic regulator.

[john HD]

junk battery?

john

[zman]

I checked the wires and connections. It all looks good. I had the bike professionally wired over a year ago. I was thinking maybe I was reading the meter on the wrong scale and I had 2.5 amps not 25 amps. I'm probably going to buy a generator next payday. In the meantime I'm going to bring the battery back to Batteries Plus and have them check it out.

[Frankenstein]

Zman, Just reading through the posts about your troubles, and I wouldn't go buy a generator just yet. If your first test really read 25 VOLTS, with field terminal shorted to ground, and meter reading taken from the Armature terminal and ground That's good.
Also, if the Amp reading was 25 amps, with the same test conditions as above, that's a good reading.
However, double check about the meter scale setting, because 2.5 volts and 2.5amps would be possible readings from a dud generator, sure enough.
However, if the readings were right:
Next, be sure that the readings you got were the right polarity. That means with the negative lead from the meter to ground, the volt and amperage readings were positive. A silly thing, but it is a question that needs to be asked. A generator outputting negative voltage and current won't work at all with an electronic regulator.
At this point, you've got to double check regulator connections or look for other possible problems.
First, hook up the regulator by the instructions, and make a separate solid ground connection from the regulator to a generator end cover screw or through bolt. Don't hook the output lead from the regulator to anything just yet. fire up bike, and look for 14 volts from the regulator output wire. If it's there, great, if not, something's not right with the regulator.
You might try and find a buddy with a known working regulator who will let you borrow it for a test. This may be a tough sell though If you do, again, only hook up the field, armature and ground connections, nothing else, and check for output at a fast idle. It shouldn't take a lot of revs to see output, and high revs will put unnecessary stress on the regulator.
If your regulator checks out, you've got other wiring issues, and you need to troubleshoot accordingly.
If your battery has 12.2 volts at rest, it probably is o.k. A little low for a fully charged battery, but a little high for a battery with a dead cell.
Good luck, keep us posted.
DD

[zman]

I was going to buy a new generator but you wouldn't believe what they want for one. I yanked out the old generator and brought it to Dave's armature service in Memphis TN. They will work on Harley generators there. They checked it out and said It works.(And they didn't charge me anything.) I threw it back in. I then snipped off the crimps at the regulator and recrimped the wires. My thinking is that I might have a bad connector when things start vibrating and I'm going to replace one group at a time. I went for a ride for an hour and then checked the battery. It was holding at 12.4v. I think I've got her licked. By the way I asked Dave what my generator readings were. He said voltage was 22v and amps were 25. Pretty much what my readings were. So now I know that a Harley generator can produce 25 amps.