Red: Low Volts

Came down and flipped on the switch and voltmeter was suddenly reading about 5.25 volts even though I knew the battery should still have 6+.  Tested the battery on the multimeter and sure enough, it was 6.25V.

Tested the voltmeter itself direct to the battery and it was reading correctly, too.

After a lot of testing and extremely unhelpful posts on both Yahoo and Reddit, I realized that the voltage was fine until I connected the coil, then it would drop low.  Disconnect the coil and it would go back up.

Also, letting the bike idle and then trying again sometimes put it back to full volts.

Another clue, start the engine and the volts would go back up to 6+ volts.

I feel like it's somehow related to checking the volts with the points open or closed...?