Electrical mystery

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Electrical mystery

Postby jOe » Thu Jan 26, 2023 6:33 pm

Ok- ‘63XLCH. Wired to the manual schematic. Good connections, no shorts. Model 61 generator, regulator marked 6V.
Lights and horn work——the tail/ brake bulb is an 1154.
6 volt . Normal brightness and function. 6V horn, good sound and function. Light on/off switch, high/low beam switch acts as normal function. The issue is the headlight bulb. It’ll burn out 6 V bulbs instantaneously. Voltage at the headlight connector was up around 12-13v. (Maybe- my multimeter is acting up). I put in a Wagner 12V bulb -H5006 if I remember correctly and it works like a normal headlight. ?
Seems like everywhere except the headlight is 6 volt and works correctly, yet the 12volt headlight also works normally.
I had the system on and running for about 20 minutes today and all was well.
I’m stumped. Different armature in the Model 61?
It works, but it’s a head scratcher.
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Re: Electrical mystery

Postby hennesse » Thu Jan 26, 2023 11:31 pm

jOe wrote:Seems like everywhere except the headlight is 6 volt and works correctly, yet the 12volt headlight also works normally.


Those extra volts gotta be coming from somewhere! My suspicion is that your charging system is putting out 12 volts, but you have a poor connection which is dropping the voltage going to the tail and stop lights.

(1) Are you using the horn condensor? If so, disconnect it and see if that makes any difference. (2) What voltage regulator are you using - original D-R 1118989 , or aftermarket?

You'll probably need an assistant for all this measuring.

Start the bike and let it idle. Turn on the lights. Measure the voltage at the ARM term on the regulator. It should be low, less than 5 volts. Measure the voltage at the BAT terminal on the regulator - should be zero, and the lights should not shine.

Rev the bike up to where the lights come on. Measure the voltage at the ARM and BAT terminals - they should be the same, and 6.5 to 6.8. Measure the voltage at the stop light switch. Measure the voltage at the taillight - all should be the same, 6.5 to 6.8.

Rev the bike up to cruising speed, and repeat the measurements.
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Re: Electrical mystery

Postby jOe » Fri Jan 27, 2023 12:50 am

No condenser, OEM regulator. I need to find my analog meter. I just talked to Kurt and he brought out some good insight into what may be happening. The generator is producing too much voltage , not being regulated to down to 6V. The horn and taillight seem to be good with it. I’ll try an 1157 in the taillight and see what happens. I didn’t notice much of a brightness change between 800-3000 rpm. An upside is the 6V horn is actually audible .
My digital multimeter is picking up way too much interference to get any reliable data.
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Re: Electrical mystery

Postby hennesse » Fri Jan 27, 2023 9:55 am

jOe wrote:I didn’t notice much of a brightness change between 800-3000 rpm.


That's a pretty sure sign that the regulator is not doing its job. On mag bikes, usually the headlight is very dim, or flickers, or is dark at idle, but then becomes steady and bright at speed. If it's bright all the time, then the regulator is allowing too much generator output to the lights all the time.

6 volt Generators produce way more than 6 volts. It's the regulator's job to keep it in the (in this case) 6.5 to 6.8 range. How does the regulator do this? It does this by grounding the F terminal of the generator (inside the regulator) - open and close 50 to 200 times per second. When the F terminal is grounded, the generator outputs full output. When the F terminal is "open", the generator outputs nothing. So here's a quick check-> with the bike running, disconnect the wire attached to the F terminal of the regulator. The lights should go out. Hook the wire back up - the lights should come back on. If the lights DON'T go out, the field coils inside the generator may be shorted to ground.

But more likely is a regulator problem. Bike turned off. Remove the regulator cover (2 screws). With the wire connections pointed towards you, the unit on the right is the voltage regulator. There is a movable contact plate attached to a piece of spring steel. Push it up and down with your finger, and it should go up and down, making and breaking the contacts. When the bike is running, it opens and closes 50-200 times/second. After 60 years of this, the spring steel gets weak or breaks. If it gets weak, it may droop and hold the contacts closed all the time, and you get full output all the time. The result would be: I didn’t notice much of a brightness change between 800-3000 rpm. If the spring steel plate breaks, you get zero output all the time.

Give those a try - no meter required. Hope this helps.
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Re: Electrical mystery

Postby jOe » Fri Jan 27, 2023 12:15 pm

Yup, everything points to the regulator. The caveat is, the Model 61 produces a MINIMUM of 6 volts. So does the Model 65 produce 15-18 volts?
Not a big deal since I don’t ride at night anyway. A ride up and down the street in this Geezerville is a big event these days.
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Re: Electrical mystery

Postby Model H » Fri Jan 27, 2023 1:54 pm

My brother and I started documenting the work we do on these old sportsters.

When my 59 XLCH went back together, the lights didn't work when we first started it.

I can't recall if we went into great detail on the testing of the electrical, but we may have.

Here is the link to our channel

https://www.youtube.com/channel/UCYpCaE ... pp=desktop

If you search our channel for 1959 XLCH No Lights, there are 5 videos (I think).

The .1 titled the videos are reconfigured for landscape style viewing.
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Re: Electrical mystery

Postby jOe » Fri Jan 27, 2023 4:44 pm

Just thinking out loud. If my Model 61 has an output of 13-15v measured at low rpm, idle speed, could a 12v regulator be used in conjunction with 12v bulbs? Not that I’d do that, but just wondering.
I tested the tail / brake light with an 1157 at all rpm ranges- worked fine.
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