1982 KZ750 electrical issues

wow,
did someone do a rewire before you bought the bike?
That brown wire powers a lot of the bike.
Yeah, there may be shorts that you are dealing with as well.

We may just unplug everything and gradually plug things back in until we have an issue. Then we'll track it down.

If you’re referring to all the taped on labels, no that was me making it easier for myself to process what went where and why. As far as I can tell the wiring harness is intact. I’ll ask the prior owner if he cut it open.

In the mean time I’ll unplug everything and follow your instructions. I really appreciate the help.

just for kicks..
I think you have a break on that white wire.

meter DC V
everything connected
ignition on/engine off
remove the jumper wire to the yellow

black probe on negative battery post
red probe both side of the white wire fuse
note voltage

You have to find 12v on that white wire with the ignition on. Essentially, you would follow the white wire back to the battery until you find 12v. The area between the 0v and 12v on the white wire will be where your issue will be. It could be corrosion, pinched wire, bad connection....anything.
This is why you have to have the circuit on...When it's off you wouldn't see the issue.

turn off bike

Haven’t had a chance to check that next step yet. Do you have a recommendation on an aftermarket wiring harness? At this point I’m wondering if it wouldn’t be less of a headache to go that route. I was looking at the Ultima wiring harness. Designed for a Harley, my understanding is I’d need to switch to Harley style controls for the blinkers.

Yeah, I have no idea on that aftermarket harness.
That would be a big job, but it can be done.