XJ Electrical problem

[Brent]

connections

That's my point. No red wired pins were touched to black. Even when the bike is charging, it's just barely keeping up. I have to keep unplugging the headlight so it can charge the battery back up, even though it shows it's putting a little over 14 volts out to the battery. Plus... my original dash problem is still there.

Hi Tod,
My reserve lighting unit did not let enough voltage through. Other dirty connections did likewise. Check voltage on each side of the various connections and also the RLU. Also check for bad ground connections (The ground straps at the turn signals are prone to corrosion) Low voltage can sure cause much trouble.,
Good Luck wrenching,
Brent in GA

[trbig]

Well, back to square one. You were correct, Steve. there's no voltage to the black wires, just the red ones.

Brent, I've checked every ground and replaced every electrical piece I could think of including the RLU, the ignition switch, the dash, the TCI, etc... Thinking I'm just going to have to do what Greg suggested and replace the whole wiring harness.

[jetmechmarty]

I haven't looked at the wiring diagram on this bike....but, have you checked the charging rotor? I think you need about 5 ohms between the slip rings. What happens if you do the monitor test with the generator brushes removed? I'm wondering if that thing might be breaking down. It's a common problem with bikes of that vintage that vibrate more than the XJ.

[trbig]

I think you need about 5 ohms between the slip rings.

No idea what you're talking about here..

With the alt cover removed, which removes the brushes from the rotor plate, the problem is the same.

Steve..or anyone.. Do the red wires that I showed in the last pic always have power to them even with the key off?

[jetmechmarty]

Does the rotor plate have two slip rings that the brushes ride on? If so, what is the resistance between them.

[trbig]

The rotor plate is one solid plate.

[BA80]

He means the 2 brass or copper rings that the brushes ride on Tod.

[jetmechmarty]

Thanks Greg. That's it. You should read 5 ohms between those rings. Much less and your battery won't charge very well. Sometimes a failing rotor will check OK when it's cold, but short when it's hot, draining the battery instead of charging it.

[trbig]

This is a new one on me.. I always thought that was a solid one piece face on these rotors.. BUT.. I checked the one on the bike and two others, and the gauge jumped around a bit but varried anywhere from 4.6-5.2 ohms on all three. I couldn't get the reading on the gauge to stand still.

[jetmechmarty]

4.6 ohms is good. How difficult would it be to get it hot (ride it) and check it again?

[BA80]

That's close enough to 5. If you cleaned them up good the reading would probably be steady. I think the problem is in the harness.

JAT.....have you checked that ground strap from the engine to the frame back by the middle drive?

[trbig]

4.6 ohms is good. How difficult would it be to get it hot (ride it) and check it again?

It's kind of a PITA. I have the three-point style crash guards and have to remove 3 points of the engine mounts to be able to take the cover off.

I don't think charging is a problem. I think it's just shorted out somewhere and drawing the power off. Since we cleaned that plug up, it seems to be charging the battery up fine, but cold or hot, the dash is screwed up.

Ansd yes, Greg, I redid that main ground there, along with the one at the R/R unit.

Gonna take it up to Ivan's this weekend and see if he can figure something out.

[jwhughes3]

Just try not to crash and leave guard and cover off for testing.

John

[dpotter58]

Just try not to crash and leave guard and cover off for testing.

John

well, it is Tod

[CaptonZap]

No idea what you're talking about here..

With the alt cover removed, which removes the brushes from the rotor plate, the problem is the same.

Steve..or anyone.. Do the red wires that I showed in the last pic always have power to them even with the key off?

I think what he was trying to say is that the resistance through the coil that the slip rings are connected to should have about 5 ohms resistance.

According to the factory manual that I have, they show a direct connection from the regulator, to a terminal on the main switch, through a 30 amp main fuse, and there to the positive battery terminal. The diagram only shows one red wire, but Steve pointed out that two would handle twice the current.
So yes, they would be hot at all times. Check the main 30 amp fuse. CZ


Oop's, please disregard the above post. I came late to the party, and didn't realize that it had moved on. Sorry, CZ