The Sportster and Buell Motorcycle Forum - The XLFORUM®

The Sportster and Buell Motorcycle Forum - The XLFORUM® (http://xlforum.net/forums/index.php)
-   Ironhead Sportster Motorcycle Talk (1957-1985) (http://xlforum.net/forums/forumdisplay.php?f=7)
-   -   Ironhead Generater light question (http://xlforum.net/forums/showthread.php?t=2079939)

Doc308 5th August 2021 22:33

Generater light question
 
The bike is a '69 XLH. The generator light came on a week or so ago, but it is charging and the battery is maintaining a good charge. I checked the connections under the nacelle and all are good. I then ran a wire directly from the generator armature pole directly to the light in order to circumvent any other issues between the 2 components and the light stays on. So, it appears that something is amiss inside of the generator. I've never had one apart aside from replacing brushes in one about 40 years ago. What would be some things for me to look for, given the description of this issue?

ryder rick 5th August 2021 22:51

A filament light bulb will illuminate if current runs through it in EITHER direction.

sleighcrane 5th August 2021 23:00

As strange as this sounds check to make sure that the generator bulb is properly in it’s socket. Happened to me once and that’s all it was. Good luck


Sent from my iPad using Tapatalk

Ferrous Head 5th August 2021 23:01

The light is connected via a diode. It only lights with current flowing in one direction. Once the generator voltage rises above the diodes level the light will.should go out.
Now the diode might have gone bad. But they seldom do.

Only way to properly check the battery is with a load tester. The genny may only be putting out 11 volts at full speed. really, you need to check the genny output.

ryder rick 6th August 2021 00:04

No diode on a 69.....

Doc308 6th August 2021 00:43

The bulb is good and tight. I checked that first and the connector was a little loose, but I dismantled reinstalled it with a small bit of shrink wrap around that part of the wire and it's real good now--as far as that goes.

Rick--when you say the bulb will light in either direction, what do you mean as far as what I might look for?

I just thought of something else. In the socket where the genny light goes, there are 2 wires: one goes to the bulb and the other seems to be attached to the side of the socket. I initially thought that it is was a ground wire. However it is live, as is the wire to the bulb. Is this correct? And--are both of these wires supposed to go the Gen port of the regulator?

ryder rick 6th August 2021 01:18

Yes there is at times power on both sides of the light.
When that happens the light is not illuminated.
When the generator has no output, power from the orange wire flows through the light to the generator.
If the generator output is more than the orange wire, the light may illuminate.
That is why the diode was added later on to prevent the dull glow during high generator output.

porch_hornet 6th August 2021 13:38

FWIW - I just solved a charging issue with my generator (77 XLCH) with a new Cycle Electric unit. HD is stamped on the unit that came with the bike, so it may be original equipment. 44 years seems a good life span. :)

IXL2Relax 6th August 2021 14:21

You might want to remove the bulb from the circuit and measure the actual voltage on each wire that feeds it. That will give you an answer to which side is low voltage and which side is higher. That might be a clue to something malfunctioning, or confirmation that both the battery and the generator are producing reasonable voltage.

IXL _______ >>>> My Motorcycle Chronicles Are Here <<<<
For Sportster Tech Info:
Ride The Sportsterpedia - A Toll-Free XLForum Information Highway!

The Doctor71 6th August 2021 14:35

There is no diode in that circuit on a '69, so let's squash that thought, up front. Unless of course you've got some bastardized wiring harness that we haven't been told about.

Quote:

Originally Posted by Doc308 (Post 5909299)
The generator light came on a week or so ago, but it is charging and the battery is maintaining a good charge.

Why do you think your electrical system is charging ? and not dis-charging ?

If you're correct, I kinda doubt that will last for long. From my "arm chair quarterback" position, it smells like your battery is discharging. To what degree is the question.

I suppose a chaffed wire could be the cause, but I suspect there would be other tell-tale signs if that was the case. (aka smoke emitting from your wiring).

Quote:

Originally Posted by Doc308 (Post 5909323)
I just thought of something else. In the socket where the genny light goes, there are 2 wires: one goes to the bulb and the other seems to be attached to the side of the socket. I initially thought that it is was a ground wire. However it is live, as is the wire to the bulb. Is this correct?

Yes, that is correct.

And yes, that is not a ground wire. It looks like it might be a ground wire, but it's not a ground wire. It does not go to ground. Think of it as a "complete the circuit", wire.

Quote:

Originally Posted by Doc308 (Post 5909323)
And--are both of these wires supposed to go the Gen port of the regulator?

NO, both wires do not go to the GEN terminal on your voltage regulator (VR). And if you check again, you'll find they do not, BOTH, go there. If they did, the light would never illuminate.

One wire will go directly to the GEN terminal on the VR. The other wire will take a longer route but will get traced back to the BAT terminal on the VR.

Movin' on.............

As others have stated, the way this light operates, is pretty simple. It's "electrical" pressure applied to either side of the light. If "electrical" pressure on one side drops below the other side, the light illuminates. (assuming of course the light is not burnt out & the wires are properly connected/not broken, etc.). As long as the "electrical" pressure on both sides of the light is identical, the light does not illuminate..... which is the normal case when the motor is running and the electrical system is solid.

Based on your description, what you have (with the motor running & the light being illuminated) is different "electrical" pressures being applied to either side of the light.

So now what ?

Get out your multi meter/ohm meter & monitor the voltage (with motor running at fast idle) at the GEN and BAT terminals on your VR. What do they read ?

Do you have an "AMPmeter" to test the output of your generator ?

Failing that, it will be difficult to accurately diagnosis.... and you're into blindly swapping parts or blindly rebuilding the generator, in the hope you find something there.

You might get lucky & a cleanup of the generator and a fresh set of brushes may resolve your issue..... but it's a wild a$$ guessing game at this point.


All times are GMT +1. The time now is 19:10.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
XL Forum® - Linson Media LLC