Battery good, no engine turnover or headlight power.

Ah yes, old_Kaw good eyes. It appeared cut to me, but I think you're right, it's just behind the frame.

Kawasaki eventually corrected the solenoid wire color discrepancy on later Kz's. That snippet must be from a much later model due to the 3-phase permanent magnet charging system shown.

Here's a snippet from a 1977 Kz650. It pretty much matches Ed's photos exactly. It also shows the wire-color irregularity on the starter solenoid. The 550's and twins are like this and quite a few others if I recall.

Often, a technician will put the wires in a more logical state, that is...connect the hot side using the yellow/red wire, but untouched examples I've come across have the yellow/red to ground.

This is actually the C1 diagram, but the charging system and starting system are same for B1. (C1 adds hazard lights.)

After googling the exact year, I was finding the same wiring configuration on the start circuits, so rather than adding yet ANOTHER file to my overworked notebook, I just snipped it from my FSM. The charging system shown is for my 3 phase permanent magnet system. I was highlighting the start solenoid configuration.

There are several wiring diagrams for the Kz650 on this link. (including a bare bones diagram) Scroll down to reply #5 on the link. Click the pic / diagram to enlarge it.
www.dotheton.com/forum/index.php?topic=47158.0