Great rotor pic, Jim.
Ok, lemme share this concept, plant a seed (or lay an egg).
Take some small rare-earth magnets.
View attachment 117439
And bury some in strategic locations in the rotor parts.
View attachment 117440
Maybe in the inner rings?
Maybe in the arms?
Maybe in the fingers?
The idea would be to have a semi-PMA, or boosted-PMA, that would be able to put out just a marginal or minimum amout of power when the rotor coil is unpowered. A crippled, limp-home capability.
Of course, the magnet orientations would be critical, since the 2 different alternator setups have the current running in opposite directions, opposite polarities, making a rotor a dedicated 70-79 type or 80-83 type.
It could help during starting.
Reduced rotor current during operation.
Rotor coil or regulator fail, unplug regulator, limp home.
Just enuff output to handle minimums, without overcharging.
I can switch lighting on/off on my XS1B, to manage overcharging. And, bikes down here don't require running lights on models older than 1975. So, my needs would be down around the 2 amp range.
Different challenge for later bikes.
A viable project?