'77 KZ 650 wiring meltdown woes

Update: I got her running!:woohoo: Turns out the Martek electronic ignition was bad. I replaced it with the complete set-up out of an '80 KZ 750, and I got spark! I put the gas tank back on her and hooked it up, shot some starter fluid down the carbs, and the old beast came back from the dead! Sweetness!
I still need a rectifier/regulator (I think). I bought the rec/reg off the KZ750 thinking it would work on my bike, but taking a closer look at it I discovered that it had 3 yellow wires that attach to the generator instead of the 2 that my bike has. Does anyone know if I can make this work on my bike, and if so what do I do with the extra yellow wire? Or do I have to buy yet another rec/reg?
A big THANK YOU to everyone who took the time to help me out with advice and words of encouragement, especially to Patton, who patiently tried to explain ignition theory to this bumbling bonehead!:silly:

Chris

UPDATE: Hooked up the 6 wire, 3 phase rectifier/regulator off the KZ750 onto the KZ650 and it appears to be working well. H2Rick on KZ650info.com was the first to advise that this would work and electrical guru loudhvx has this to say on the subject:
"Theoretically, using a 3-phase combo reg/rec can work for a 1-phase alternator as long as each of the 3 reg/rec circuits is capable of handling the extra current. Obviously, if you are getting the same power through 2 circuits instead of 3, the 2 working circuits need to handle 16.7% more than it was made to. The thing is, because manufacturers like to use parts they are already using, there is a chance that the 3-phase reg/rec uses the same parts in each reg/rec circuit as the 1-phase reg/rec. In that case, the 3-phase reg/rec can be used for 1-phase operation.

There is one other minor issue which I suspect is not an issue at all. The alternator puts out pulses of power. The battery smooths out the pulses mostly, but not entirely. The voltage detection circuit is designed to ignore small amounts of ripple in the battery voltage. If the ripples are larger (as they are in a 1-phase system) it may slightly alter the regulators operation. The battery voltage may end up slightly higher or slightly lower depending on how it handles ripple. A well-designed circuit will not be affected. BTW, Regulators are designed to sense the average voltage, not the peak voltage, and not the RMS voltage.

I guess bottom line is try and see."

So I did, and it seems to be working. I had to splice the brown voltage sensing wire from the R/R into the brown wire (a switched 12V source)that goes to the brakelight switch as the original R/R doesn't have this wire. Checked the battery voltage at terminals and it ranged from 13.33 at idle to a high of 14 volts at 5000 RPM. Not perfect, but I think it'll do. And best of all, no more meltdowns! The $175 ratbike lives!