The wiring: there is a little wiring assembly that is a large RED wire between the battery (+) post and the starter solenoid, and out of that circuit also comes a smaller RED wire, from the solenoid side (Honda crimped the two wires together in the ring terminal at the solenoid). This is the RED wire that goes to the fuse, which then goes to the keyswitch. I have the K2: the wiring is the same as K0/K1 except for the turn signal beeper. The starter solenoid, as you've surmised, grounds on its "low" side at the handlebar button to activate it. That's the YELLOW-RED wire. The RED-WHITE wire is the incoming charge from the rectifier (which is fed by the alternator). That's almost the whole wiring!
You can get that nice black jacketing from Del at
www.vintageconnections.com: he's a great guy. He sells kits to do these bikes, with jacketing, connectors, the whole 9 yards - or individual pieces. The jacketing he sells is superior to Honda's old stuff, as it does not get brittle over time, and is much more flexible. I'm using it on all the rebuilds I'm doing.
