Finally got around to plugging in the new ignition switch. That got the starter to turn. Wanted to be sure it was cranking motor so took off points cover (two screws) and could see starter was turning crankshaft. Carbs are still out but at least got one problem solved!
Well, I believe the offending party is the ignition switch. Used that blocky ignition switch drawing from the wiring diagram and found brown wire did not connect to yellow wire as it should. Neutral indicator that runs through engine stop/run switch. Also, red to blue was flaky, has to do with taillight. I could wiggle key and get it to read a couple of ohms but mostly stayed open. (I already had hit the switch with De-oxit and that didn't help.)
I'll also note it was easy to check start push button. I had the right handlebar control apart already because of pulling carbs. I could get meter leads in the back and check the button.
Any suggestions for where to get a good replacement ignition switch? I've seen a lot out there so advice would help me narrow it down.
Edit: I got impatient and pulled the trigger on one listed for '81 KZ750E...