I rode my '74 H-D (Shovelhead) several times with a dead regulator/rectifier assembly, which is a weak point on that engine.

In each case, the engine sputtered a bit while moving and ultimately quite while idling. Putting my hand in front of the headlight immediately showed the problem.

Turning the headlight off (a nice feature on an old bike) would allow me to kick-start the engine and ride home. Once, upon arriving, the battery measured four volts with no draw, yet the point-style ignition system was still working.