Mo' "Motocycle" Musings . . . . .
(I duz knoes hows to spels)
AN ANALYTICAL EVALUATION:
The left windings of that magneto is associated with the electronic ignition.
It being variable frequency AC and is DC converted within the ignition module.
Part of the magnetos right half windings are associated with charging the 6 V 4 AH battery
(Now isn't 4AH about equated with the "power punch" of 4 "D" cells )
And the lighting looks to be using variable frequency AC from a part of the mags right half windings.
BUT on the 400 wiring diagram that I consulted, there is being an AC shunt regulator that goes to ground from the light line.
All that would be needed is vibration . looseness or corrosion to corrupt that grounding of the shunt regulator and then the AC lighting voltage could go to max at max speeds.
(That's where the mentioned road testing and "lashed on" monitoring of the light voltage supply comes into play.)
To evaluate AC shunt regulation, the ground connection could be removed and then a clip lead used for grounding.
Get up to max output voltage and then disconnect the grounding, to see just how HIGH that voltage could get, without its shunt regulation being provided.
Now, some of the " you are a peein' " folks need to fill me in, but isn't there some requirement that if you park on / beside a small rural two lane road overnight, that you need to leave your park lights on.
We have no such requirements here, on the AMERIKANSKI scene.
That seems to be the manner, that the ( P) switching on the unit is being arranged, in respect to the way that the battery connection is being routed. to a portion of the lighting
No further info from me, until I see if the originator ever shows up again.
73's de Edd