[wwest]

For #1 my statement was "looks like it might be", so I was wrong.

But my #1 statement was DEAD ON...!!

Show me the regulator circuit/component that prevents "the" capacitor from being overcharged as the battery voltage rises if you would, please. Insofar as I can see the DC to DC upconverter runs open loop.

Tach signal is provided directly from the CDI and when it begins to self-fire due to the SCR voltage rising too high (or to fast) the tach "jumps". If it happens to "jump" too high in frequency the rev-limiter locks up, again a design fault due to excess battery voltage, and the engine now cannot be restarted absent a few seconds with key fully off.