So, I'm baffled here. My best guess is that the voltage regulator has already gone out on this bike once, and that the one that is now bad is not the original.
I"ve looked at the wiring diagrams and none seem to be exactly like mine. There's 5 wires going in/out of the regulator. All the wiring diagrams I've looked at have 4 wires on the regulator - 2 AC in, 1 DC out and a ground. There is one case where the regulator has 5 wires, but, in that case, there is a diode in line between the regulator and capacitor, but that's not the case here as if there were a diode, it would be attached to the outside of the regulator.
Also, the wires coming from the generator look wrong. On the bike side, there's one blue wire going to one terminal in the plug and two yellow wires going to the other terminal. That has two yellow (maybe orange) wires plugged into it without a plug. Sorry about the blurry pic, but you can see the colors:
Here's the one I took off my bike:
Now, to me, the wires look like black(1), yellow(2), red(3), yellow(4), green(5). Of course, I'm red/green colorblind, So I'll call em 1, 2, 3, 4, 5. Wires, 2 & 4 are inputs from the generator. And, they produce 40-60 VAC while the bike running. wire #3 goes to the positive side of the Capacitor, and wire 5 goes to the negative side of the capacitor, as well as being split and grounded to the case of the regulator.
Then there's wire #1. I'm holding it in the index finger of my hand in the previous pic. No idea where that one goes or what it does. It's not a ground. And, if it was supposed to be, it's not grounded any more.
What I do know is that I can put 12VDC to the positive and negative terminals on the capacitor, and that powers all the lights on the bike.So, I don't think it's another power wire. And, there's no resistance between it and either of the other two generator wires, so I don't think it goes to the generator.
So, here's why I'm baffled. I tried hooking up my other regulator/rectifier. It's brand new, but I guess I've never actually checked to see if it works. But, when I hook it up, I get -2.63 VDC between the power wire and the ground.
Any guesses as to what the #1 wire is or where it's going? How about my weird voltage output? Any guesses there?
I did find a replacement regulator rectifier that is supposed to be a replacement for the discontinued stock item, but I fear I'll just end up dropping $150 on another part to find out it doesn't fix the problem.
Also, what exactly does the capacitor do? I'm assuming it's just a filter to keep the lights from flickering based on the RPM of the bike. What would happen if it were removed? Can the electrical system work without it? Any reason not to just eliminate it? I tried my new regulator wire with and without the capacitor - didn't make a difference.