I was stumped by wiring too until I got the color diagram from the back of the clymer manual, then took the black wrapper off my wiring harness (removed from bike) and physically followed each wire by colore to where it ended up. I referenced each color and wire to the diagram while cleaning it. It took a few hours, but now I "aint sceered" by anything electrical on my bike. I've started mixing 750 and 550 parts when needed and it still appeatrs to be working fine. Get the book, My cb750, it is the best reference for lots of stuff.