Mystery generator, and problems charging

Scrap or repair generator?

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TMIB
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Mystery generator, and problems charging

#1

Post by TMIB »

I've been having some trouble with the battery charging on my '54 Pan.
History: When I first got the bike it had a voltage regulator mounted in the toolbox. It was an unknown type, 2 unit. I replaced it with a Delco Remy unit from eBay and moved it to the correct mount on the left of the bike on the coil. (This is a '54 FLE) It was supposed to be the right part, but after driving a while, I found it would not charge the battery when the headlamp was on. As part of my troubleshooting, I found the part number on it which did not map correctly to the unit I thought I had bought. This was actually a Delco Remy 1118708, which I don't see in any of the documents that list D-R part numbers.

I replaced it with an actual Delco-Remy 1119187, which should be a Harley # 74511-51A.
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This did not fix the charging problem however. I don't have a 30A ammeter, just a 10A one, so my troubleshooting is somewhat limited. Since it was unlikely that two different regulators were bad, I decided to have a closer look at the generator.

The generator on the bike is a 2 brush model, no fan, and is not an actual Harley part. There is no stamp on it with a part number. It could be a reproduction unit of some sort.

It has a 1 year warranty sticker on it from 2003, so old, but not OEM.

It looks to be wired correctly internally, but the terminal labeled "F" is closer to the engine, with the "A" terminal forward. This is reverse from how all the OEM ones seem to be (from my limited research). It's wired correctly to the regulator though, with the "A" terminal going to "Gen" and the "F" terminal going to "F". ("Bat" goes to the battery of course.)


Image
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Without a "growler" or 30A ammeter my testing is somewhat limited, but the field coils don't seem to be shorted. I cleaned up the commutator by light sanding with 1000 grit sandpaper to clean up oxidation, then cleaned it with some alcohol. I re-greased the needle bearing in the endcap and reassembled everything. It does not seem to have helped.

The "gen" light is very dim compared to the oil light. On a 15 mile ride with the headlamp on, I had to switch it back off when the bike started to stumble. This made it run smoothly again. (I switched back and forth a few times to confirm the behavior). After stopping, I checked the battery level and it was at 4.5 volts, not the expected 6 or so.

Riding back home, I kept the light off the whole time. (The ride is about 30% freeway, 30% 45 MPH road, and 30% 25 mph dirt road.) Upon arriving home, the battery still measured 4.5 volts when the bike was running.

I tried my cheap 10A digital ammeter anyway, connecting between the "bat" terminal on the regulator and the Battery positive lead. Readings were switching around multiple times per second, so not useful.

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My first inclination is to scrap this mystery generator and get an OEM one from somewhere. I want to stick with a 2-brush model. But if I am missing some simple/obvious problem, I will try that first.

Any ideas?
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Re: Mystery generator, and problems charging

#2

Post by RooDog »

Is this a 100 point restoration, or do you want something that will function, keep the battery hot, and not leave you stranded?
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Re: Mystery generator, and problems charging

#3

Post by RooDog »

?
TMIB
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Re: Mystery generator, and problems charging

#4

Post by TMIB »

Definitely not a 100 point restoration. I like things to look original, but am not going to be competing in AMCA or anything like that.

I want to keep things 6V, and I'd like to keep the left-mounted voltage regulator setup that this bike should have if I can.
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Re: Mystery generator, and problems charging

#5

Post by 59Panman »

Did you "Flash" the regulator to set the polarity?
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Re: Mystery generator, and problems charging

#6

Post by TMIB »

59Panman wrote: Tue Jun 21, 2022 12:09 am Did you "Flash" the regulator to set the polarity?
Yeah, every time I had it disconnected.
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Re: Mystery generator, and problems charging

#7

Post by awander »

Stick a voltmeter across the battery, and with the engine running at a decent speed, short the generator "F" terminal to ground..

If the generator is good, the voltage will go up.
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Re: Mystery generator, and problems charging

#8

Post by TMIB »

awander wrote: Tue Jun 21, 2022 12:17 am Stick a voltmeter across the battery, and with the engine running at a decent speed, short the generator "F" terminal to ground..

If the generator is good, the voltage will go up.
Thanks. I just went out and tried this.

Battery showed 5.3V with the engine not running.

Fired it up and it was jumping all over the place, but eventually started showing 5.4V

I disconnected the "F" wire from the regulator (which goes right to the "F" terminal on the generator) and grounded the wire. No difference. I saw 5.3-5.4 volts still. Revving things up a bit made no difference.

I'm thinking at this point that I should buy a model 61 OEM generator off eBay. This would match the regulator I have, though of course there is always a gamble that it might not work.
Last edited by TMIB on Tue Jun 21, 2022 2:37 am, edited 1 time in total.
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Re: Mystery generator, and problems charging

#9

Post by awander »

I should have mentioned, you also want to make sure that the cutout relay in the regulator is closed when you make that test.

The cutout relay connects/disconnects the generator "A" terminal to/from the battery. It is supposed to close any time that the generator voltage is higher tan the battery voltage, but it is possible that your cutout is defective.

You can hold it closed by hand to make the test.
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Re: Mystery generator, and problems charging

#10

Post by RooDog »

Let's not forget the "motor" test.
Google it....
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Re: Mystery generator, and problems charging

#11

Post by TMIB »

awander wrote: Tue Jun 21, 2022 12:52 am I should have mentioned, you also want to make sure that the cutout relay in the regulator is closed when you make that test.

The cutout relay connects/disconnects the generator "A" terminal to/from the battery. It is supposed to close any time that the generator voltage is higher tan the battery voltage, but it is possible that your cutout is defective.

You can hold it closed by hand to make the test.
Ok, so this time I was seeing 5.3 volts when running. Closing the cutout relay drops this to around 3.4 volts, whether the "F" wire from the generator is grounded or not. (i.e. there is no difference when grounding the "F" terminal from the generator.)
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Re: Mystery generator, and problems charging

#12

Post by TMIB »

and for a sanity check:

This one is the cutout I need to close for this test, right?

Image
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Re: Mystery generator, and problems charging

#13

Post by awander »

Yup, that's the cutout.

Did you try revving the engine during the test?

If so, looks like your generator is bad, or there is some kind of wiring issue.
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Re: Mystery generator, and problems charging

#14

Post by TMIB »

awander wrote: Tue Jun 21, 2022 3:25 am Yup, that's the cutout.

Did you try revving the engine during the test?

If so, looks like your generator is bad, or there is some kind of wiring issue.
Yeah, revving did not seem to make a difference. The fact that there is a big drain when closing the cutout relay when everything is otherwise connected is a pretty good sign that something is wrong with the generator.

Wiring seems to be OK, tested continuity at each end, and traced them. Generator "F" terminal to "F" on Voltage regulator, Generator "A" terminal to "Gen" on Voltage Regulator. (Gen light is also running off the "A" terminal.) "Bat" on Voltage regulator to positive battery terminal.

I went ahead an ordered a used Model 61 Generator. We'll see what kind of condition it's in when it arrives.
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Re: Mystery generator, and problems charging

#15

Post by TMIB »

To follow up here, I bought a used Cycle Electric generator off eBay. Hooked it up and... nothing. No charge coming off it. So I pulled it back off the bike, and bench tested it by hooking a battery + to the "A" terminal, jumping the "F" terminal to the mounting stud, and then applying battery - to the other mounting stud.

I got a bit of a twitch from the armature, but it did not spin. I played around with it a bit, and the most I could get was a twitch once in a while.

So I dug into it and quickly found the wire from the negative carbon brush was broken at the connector. It was making intermittent weak contact. That was an easy fix, replaced the short wire with a new one, and then the generator spun just fine when power was applied.

I put it on the bike and hooked up a multimeter to the generator (which was not wired to the bike yet). With positive multimeter lead to the "A" terminal, and negative to the engine case I was putting out something like 2.8v at a speed a little above idle.

Temporarily grounding the "F' terminal jumped this to something like 30V or so. (I'd guess I was about 1500 RPM, did not have my tachometer hooked up).

So in general, I'd say it's working! The real test was today though, I drove to work (30+ minute drive plus a gas stop) with the headlamp lit the whole way, and had no problems whatsoever. I'll do the same on the way home tonight and check the voltage when I arrive, but early indications are looking good.
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