Up and down with engine revs makes sense to me, but frequency should be independent of the regulator (because it is before it, and can be tested disconnected from the regulator), no? I'm not familiar with inverter type.
Anyway, let's say 1,500 RPM x 4 poles x 60Hz would equal 360,000. That seems way high

Boy I wish I knew more about electronics

mrkprsn,
Yeah it is a brand new conventional lead acid 6V 13Ah battery. I had trouble with a couple of the cheap sealed lead acid batteries which lost a charge quickly (even though amp hour rating was high) so I went with a new conventional. I might have ruined the SLA batteries by draining them too far, and I recently upgraded my trickle charger because the old one continued to charge even after the battery was fully charged. Anyway, this battery goes right back to 6.3V when the bike is turned off again so it seems to be holding a charge fine.
Agree, testing the voltage at the (ignition) coil might show it dropping more. I also tested at the battery and it dropped while running, just not as much. More like 6.2V instead of 6.1V at the coil. Either way, it didn't go up as I would expect it to while running. All of this with no lights on.
How do I individually test each of the yellow AC wires? Positive multimeter lead to one yellow and negative lead to a ground? Or do I just reverse the multimeter leads to the opposite yellow wires? To test voltage so far I connected one multimeter lead to each yellow wire with the bike running off the battery and got 24V-42V depending on RPM.
There IS continuity between the yellow wires, and there IS also continuity between each wire and ground, which I understand is by design:
One question I have: Does the 6A coming from the stator mean that the bike is drawing 6A, or does the stator always output its max amperage and the regulator throws off the excess power as heat?
One more test I plan to do is reverse the polarity of the inline ammeter coming from the stator and make sure it reads zero. If the ammeter is bi-directional, could the power be flowing TO the stator instead of from it? Maybe the stator is drawing power by grounding out in a way that isn't by design... like a fault.
Heading out to a local Italian car and motorcycle show

Edit:
Ugh. motorcycle show was postponed but I didn’t see it on social media so I rode all the way over there (different bike) for nothing on a beautiful day. What a tragedy

Bill I disconnected the ignition switch and jumped it out with no change. Appreciate the suggestion. Keep them coming.
Also, I tested the ammeter on both yellow stator wires, and with the ammeter polarity reversed too. Four possibilities and I get just over 6 amps in every case.
Scratching my head
