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82 XS400SJ Charging system nightmare


Ebola Monkey
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There is a diode under the seat that controls the voltage to your battery if its weak or gone it will not charge!

Diode under the seat is part of the headlight circuit. It's Fresh.

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Diode under the seat is part of the headlight circuit. It's Fresh.

Diodes work or they don't 99.9% of the time.

I found my Haynes book of myths for this bike! Brings back memories! It looks like you are in for an oily mess. The starter drive is in here and the starter motor is sealed as well.

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Diodes work or they don't 99.9% of the time.

I found my Haynes book of myths for this bike! Brings back memories! It looks like you are in for an oily mess. The starter drive is in here and the starter motor is sealed as well.

I tore the generator apart today. The cloth wrap on 1 wire from the generator was worn, but the plastic insulation was fine. Other than that, everything looks to be in great shape. There are no visibly damaged areas on the wire sleeve, and nothing looks pinched.

I also cleaned up the other used regulator I have. It has 1 wire worn through the insulation in the same spot, but it's down to the wire, and someone had done a really bad tape job on it. It also has a couple area where the wire sleeving is cracked.

Now, with my meter both armatures OHM out to the exact same numbers (1 - 1.1ohms), and both field coils OHM out to the exact same numbers (3.4ohms). Considering my current wiring is in better shape, should I even bother replacing them?

I destroyed the gasket in the process of getting the armature, and coil out so now I'm waiting until Monday at the very least for that to come in.

I don't know what else to do. I can't start buying "know good" parts for this thing. They're too damn expensive, but with used parts I don't know what I'm getting because everybody says "the bike ran perfectly before were tore it apart". I think we all know that's BS.

Battery - Known good

Stator - Have 2 both test out identical

Field coil - Have 2 both test out identical

Regulator - Have 2 both test out almost identical

Rectifier - have 2 both test out almost identical

It's getting to the point where I want to put it back together and sell it.

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SOLVED!!

After taking the generator apart last week I decided I would keep the current one instead of replacing it. I had a new resistor cap on order because one was "leaking", and would shock the hell out of me any time I got near it. I also doubled up my battery ground, as I had a spare ground cable. So now 1 ground to the engine, and 1 to the frame right next to the battery.

Charged the battery, and let her rip.

12.3v @ idle

A few revs, and

14.5-14.6V @ >2000rpms

I don't know if the cap helped or not, but I'm guessing the second ground the big fix. I checked for voltage drop on the original cable, and it was good. Maybe there's a crack thats screwing up the ground with engine vibrations, or something. That could help explain the erratic charging. All that matters is that it seems to be working now.

Thanks Again to speedshop, and Drewpy for all your help!

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