1976 Ironhead Sportster
Ignition Switch, Electrical, and Wiring
Before I bought this Sportster, the main wiring harness had been cut in half, right behind the headlight bucket. Apparently, this was an attempt by the previous owner to remove and replace the cracked bucket.
I traced, then drew out in a notebook where all the wires started, where they ended up, and their color. The factory service manual is invaluable for this. It includes the original wiring schematics, which I constantly cross-checked my own notes with. I also took pictures of everything I disconnected; solenoid, voltage regulator, circuit breakers, etc.
The new battery was filled with acid, charged and installed - I'll be using it to test all the electrical system and wiring.
Because I was not going to re-use the bulky hand controls which originally came on the bike, wires for the start and stop buttons and turn-signal switches were no longer needed. They were tagged and removed.
The replacement ignition switch I'm using is made by Pollack. It has a car-style twist-start feature, which will eliminate the need for both the start and stop buttons. The original Sportster horn will be kept.
A three-way toggle switch was mounted on the back of the headlight bucket and wired up for high-beam/off/low-beam.
With everything wired up, I re-checked all connections with the battery and test-light, and everything worked well. Turning the key, the headlight and taillight came on, and both high-beam and brake-light worked. Twisting the key, the starter spun the motor over, the ignition points sparked, and there was spark at the plugs.
With the electrical system now complete and working, I was able to crank the motor and do a compression check. Both cylinders showed to be within specs.