So I have a attached a picture of the wiring panel after I have gotten some of the wires from the old harness out of there. I don't think I can use the original wiring harness because the PO totally mangled it by splicing in a toggle switch to somehow cut the ignition out of the loop. So the two wires coming out of the little diode for the starter motor are spliced into the toggle switch.
I'm afraid this is going to sound harsh. But, I think the observation is valid anyway. So, here goes. Put on your thick skin, OK?
When you're done, what wire diagram will be valid for your bike? The 75? The 76? Or, a hybrid that only you, if anybody knows how to manipulate/follow?
I'm skeptical your old harness is really "totally mangled". I can believe it is modified in a way you don't understand. If you get the correct wire diagram for the bike and then restore the modified sections, you have a bike that is easily understandable by anybody that can read stock wire diagrams. If you do make a hybrid, you are going to have to figure out how it all works correctly, anyway. Why not understand and make something serviceable in the future?
I suspect you are trying to evade wiring understanding by changing parts wholesale. But, in the time you have finally adapted the older harness into something functional, you could have simply mended and reversed the changes made by the P.O.
It's your call, of course. Maybe my observations/guesses are wrong.
Anyway, you should know that the diode you mentioned is not for the starter motor. It's function on the stock (76) bike is to keep the neutral light from coming on when the clutch lever is pulled in.
Your bike (76) originally activated the starter solenoid by placing 12v to one solenoid terminal from the starter button, and applying 12V return (neg) on the other terminal via either the nuetral switch or the clutch switch.
The 75 put 12V on one starter solenoid terminal whenever the Key switch is activated. 12v(neg) was applied to the other solenoid terminal, when the starter button was engaged AND the Starting Safety Unit enabled the starter button after either the clutch or neutral switch was active.
By the way, Honda changed the function of the Y/R wire from providing 12V(Neg) to the solenoid in 75 to providing 12V (pos) in 76. What bar controls do you plan to use?
Have you found the 76 wire diagram in the shop manual yet?
Cheers,