Thanks for the replies. More to think about, which is a good thing! I didn’t think about
the 57 Big Twin needing a “kill” circuit. Not sure it has one, but in looking at
this photo, still not sure!
There’s the kill wire from the vacuum switch to the mag, but that’s only attached
to one set of points.
In the photo, I see a wire I labeled that runs from the harness plug to the vacuum
switch. If this is for the engine kill circuit, it wouldn’t make sense to kill one cylinder.
In looking at the wiring diagram, my labeled wire looks like the ground for the starting circuit?
For the record, this motor does not have a generator.
Prepare to be boarded!