Thanks Mike, every thing is working now. I never thought that the brake lights would be fed from the 6V side. Like I said, wiring schematics and electrical aren't my strong point. The horn works, as crappy as it sounds, just an annoying buzz. While I was testing the horn circuit I squeezed the brake lever and I saw the brake light come on. Eureka! Headlight, speedo lights, tail lights all work on 12V and the horn and brake lights work on 6V.
The single white wire I have on the opposite side of the other white wires is for the speedo lights.
On to making cables for the carb and timing the engine are next on the agenda.