So frustrated, any help is appreciated.

Something on my charging system took a dump. I can run for about 40 minutes on the battery, but then it dies out.

The battery is less then a month old.

Rectifier is brand new as of today from Oregon Cycle Parts

I did the Dynamo voltage test as per my service manual, and get 0 DC volts.

I get 0 ohms resistance from any combination of the armature leads, but it does not read open.

I also get 0 ohms (but not open) doing the field coil test.

I have no way of testing the voltage reg, as I dont have a light bulb, or an adjustable power source.

This all started with an electrical fire, where the white (main) wire burned up, but I took the whole harness apart and replaced it.

Should I try replacing the voltage reg first? Is it possible both the field coil and the armature went kaput?

I am so frustrated with this thing.

Thanks.

Check out this chart that electrosport provides on their website. Someone suggested I use it a while back when I was having charging issues and it helped me out a lot! It can be a little tricky to follow, but once you figure out that puzzle, it will lead you in the right direction!

www.electrosport.com/media/pdf/fault-finding-diagram.pdf

~Clutch

This one looks like the right one to test the regulator/rectifier:

www.electrosport.com/technical-resources...de-testing-guide.pdf

The regulator/rectifier are separate units on the 76. the service manual says



But I dont have an adjustable voltage source.

regulator is bad, they're cheap

Doesn't your manual describe the regulator bypass test? The test puts full power to the field coil. It lets you know if the regulator is bad. All you need for the test is a voltmeter.

Your bike is setup where the field coil gets 12v all the time on it's brown wire. Then the green wire of the field coil gets grounded by the regulator, by varying degrees, in order to control the magnetic field. The strength of the magnetic field determines the stator's output power.

To do the test, you remove the regulator. Then you jumper the green wire to the black wire at the regulator plug. DO NOT REV THE ENGINE UNTIL YOU ARE MONITORING THE BATTERY VOLTAGE. The alternator will be at max output (if everything is working and all of the wires are good), so only let it idle. Connect a voltmeter to the battery, and check the voltage as you rev it a little. IF the voltage doesn't go above 13v pretty quickly, then either your field coil is bad, or the stator is bad, or the rectifier is bad, or the wiring is wrong or bad.

I suspect it's the regulator, or the wiring, if there was a fire.

My manual says almost what you said, but it says to disconnect the rectifier, put the voltmeter red to the Rec white and the ground to chassis ground, remove/jump the green/brown, and then start it. I get 0 dcv doing this test.

Yes, to be safe, you could disconnect the output of the rectifier (white wire) from the bike (but still leave the yellow wires on the rectifier), and measure from black to white using a voltmeter. Do this test first, but be aware you are not testing under load. With white connected to the bike, the test will be under load, but is dangerous if you don't monitor the battery voltage closely. If it doesn't pass the no-load test, then you don't need to do the loaded test.



I'll have to check, but I'm pretty sure the manual should say "jump green to black" on a 76 750 twin. Brown to green would be for the 77 kz650, and the early kz400's. The 750 twin is different. Your earlier post, with the manual image, confirms what I'm saying. Notice the field coil has a wire directly to the positive 12v. The regulator controls the negative side of the field coil.

Well, since I know the wiring is good, and I know the REC is good, and my DVOM broke, I decided to just start throwing parts at it.

Found a REG at a local scrapyard. My voltmeter is going crazy, but the votage does go up 2-3 volts when revved, and if I turn the ign/headlight on for a few and then start it the headlight gets noticeably brighter.

I think its fixed.