Electrical Troubleshooting ‘79 GL1000

[MattMcCoy]

Have a couple of small electrical issues that I’m still reading up on, but wanted to get a conversation going as well. I’m working on a ‘79 GL1000. It’s been retired for a number of years, but it was maintained very well and put up properly. I have a new AGM battery, changed belts, fluids, filters, and checked continuity on the fuses so far. Starts, runs, and stops — so much fun to ride! My two issues:

-Yellow wires (soldered) from stator get very hot. Charging system is weak and volts don’t seem to increase on battery over 3000rpm.

-I do not have gauge/tank lights.

Points have been replaced with electronic ignition, and updated rectifier/regulator, and I cleaned contacts on fuse panel. I hope to check engine mount ground, stator wires at the regulator/rectifier, and the brown/white wire to clusters today.

Am I missing anything?

Thanks,

-Matt

[gltriker]

Have a couple of small electrical issues that I’m still reading up on, but wanted to get a conversation going as well. I’m working on a ‘79 GL1000. It’s been retired for a number of years, but it was maintained very well and put up properly. I have a new AGM battery, changed belts, fluids, filters, and checked continuity on the fuses so far. Starts, runs, and stops — so much fun to ride! My two issues:

-Yellow wires (soldered) from stator get very hot. Charging system is weak and volts don’t seem to increase on battery over 3000rpm.

-I do not have gauge/tank lights.

Points have been replaced with digital ignition, and updated rectifier/regulator, and I cleaned contacts on fuse panel. I hope to check engine mount ground, stator wires at the regulator/rectifier, and the brown/white wire to clusters today.

Am I missing anything?

Thanks,

-Matt

Here's some charging system trouble shooting information.

https://www.randakksblog.com/comprehens ... eshooting/

Tell me about the updated rectifier / regulator. Where did you buy it and what information do you have about the unit?

[Track T 2411]

Heat is caused by excessive resistance, which is often caused by corrosion, and it can be a never-ending cycle. I would suggest a close inspection and cleaning of the yellow wires' terminals at the regulator/ rectifier plug, as well as considering redoing the soldering job. You can also reinstall a proper plug aft that location. I have one bike that required cutting out several inches of the yellow wires in each direction from the plug due to corrosion. It can be a PITA soldering those wires down in the frame, lol!

[Whiskerfish]

If they are soldered properly they will get warm but I don't think they should be hot. Makes me think maybe your rectifier / regulator is not working properly and drawing too much current. Are all 3 equally hot? Might be worth cutting them and doing the Alternating Current output check to double check the stator output. If that is good then I would definitely look at the rectifier next

Yes to what Track said. I have added extensions to several without issue.

[MattMcCoy]

Thanks for the advice. The reg/rec doesn’t have any markings on it, so I’m not sure of the brand. When I disconnected its harness, I see corrosion/discoloration on all three yellow wire terminals from the stator, so I’ll clean those up and pack with dielectric grease. Resistance testing on all three wires show 0.07 ohms, have continuity, and are not grounded. I think that might mean the stator is OK.

[pidjones]

Thanks for the advice. The reg/rec doesn’t have any markings on it, so I’m not sure of the brand. When I disconnected its harness, I see corrosion/discoloration on all three yellow wire terminals from the stator, so I’ll clean those up and pack with dielectric grease. Resistance testing on all three wires show 0.07 ohms, have continuity, and are not grounded. I think that might mean the stator is OK.

Could be. Great if it is! Use a much better high-current connector, or solder and shrink wrap. They live where not only road and atmospheric moisture gets on them, but near the battery vent (very corrosive fumes). I had the regulator fail full output on my '79, and replaced it with a cheap Chinese reg/rect. Just provide the sense from the old regulator connection. I also replaced the old analog voltmeter with a digital (put it in the same case) so I can keep an eye on it now.

[MattMcCoy]

If they are soldered properly they will get warm but I don't think they should be hot. Makes me think maybe your rectifier / regulator is not working properly and drawing too much current. Are all 3 equally hot? Might be worth cutting them and doing the Alternating Current output check to double check the stator output. If that is good then I would definitely look at the rectifier next

Yes to what Track said. I have added extensions to several without issue.

I’ll do the AC test on the stator today and then test the rec/reg unit. This bike was maintained well and the wiring is great. It’s a joy to work on.

[441Victor]

On my 77 , I chased the 3 wire gremlins for months . Yes , I had eliminated the 3 wire plug and soldered them nice and neat .
One night , I was kneeling on the floor to hook up a charger and i spotted a bit of tape unrolling on the wiring harness , directly above the 3 wire joint . This is partly hidden by a vertical frame tube. So I un wrapped a section of this harness to discover another set of 3 crimp on wire splices . These looked like factory splices :
partly transparent . Trouble is that one of them was broken and melted to a charred mess.
That means that the PO thought he fixed the problem , but it was actually hidden about 4" farther up the frame .
I keep this blob on my desk for show n tell . I have never confirmed if this splice was factory , or some previous repair had replaced the plug assembly by splicing it in further up .
hope this helps
Bob

[MattMcCoy]

Thanks for the advice. Stator seems to check out. I cleaned everything up, but all three yellow wires still get very hot and volts don’t seem to increase much over 3,000 rpm. I did a diode test on the rec/reg, which it didn’t pass, so I think I have my culprit. I haven’t figured out why I don’t have gauge lights yet.

[Shadowjack]

If it didn't pass your test, that should be the problem. The comment was made that heat results from high resistance, which is true. As current flowing through a particular resistance rises, heat rises. Conductors have a given resistance per unit of length, so if the yellow wires are getting hot along their length, that means that the current flowing through them is very high: not much regulation. Actually, it sounds like a completely shorted regulator.

[MattMcCoy]

Appreciate it. The stator is reading ~0.8Ω, however spec is 1-2Ω. I read anything above that and the stator needs to be replaced, but no mention of what lower resistance could mean.

[Whiskerfish]

You really want to do the A/C check. It can be a bit tricky and a extra set of hands is helpful. Read A/C voltage from 1 yellow wire to each other then the next one etc. Looking for 50-55 Volts A/C. Be careful not to allow them to touch the frame or each other.

[MattMcCoy]

Got an extra set of hands to help test AC output from the stator. Here are the results on each pair of legs @ 3,000 RPM.

A to B ~20 VAC
A to C ~20 VAC
B to C ~5 VAC

There are three separate splices between the stator and the harness that connects to the reg/rec, so I guess I’ll cut upstream and rule out bad connections, but it looks like the stator will need to be replaced after all.

[Whiskerfish]

Yea that is not great. i forgot to mention that you want to be at about 3,000 rpm and have those wires disconnected from the rest of the charging system. If those were not done I would do so before calling the stator bad.

[MattMcCoy]

Appreciate it. The AC test was done at 3,000 RPM and the reg/rec removed, but there are three splices on all three yellow wires between the stator and the reg/rec harness, where I took my measurements. The connections look great and are well done, but I’ll do my due diligence and rule those out for age failure. I connected a spare reg/rec from an ‘83 1100 to test, but was getting over 15 VDC on the battery, so I removed it.

Checked the brown/white wire, which seems to control gauge/tank lights. I’m not even getting 1 VDC from it on the distribution block, fuse box, or attached harnesses. Looking at the schematic, it seems there are two connections at the ignition, so I’ll check those, and one at the turn signal control.