Nice explanation and graphic Frank.
Back when I was trying to figure out the very erratic running HD-15
with this “whacky” ignition, I did some testing and made a diagram
trying to make sense of if things were working correctly as far
as the coil grounding system.
Thinking back, all I know is I was using an ohm meter checking continuity
as I slowly spun the flywheel. I have no recollection of if the points,
and condenser were hooked up or not, but I remember getting readings
on the meter that made no sense.
Perhaps one day I’ll try again, but maybe with a different flywheel if I
have one, or can find one.
Prepare to be boarded!