TOPIC:

So I have a frustrating issue. I have a 1981 KZ100K LTD. Have power to everything except for the starter switch. Starter works fine. Bypassed starter. Turns over but no fire. Replaced regulator / rectifier. No change. I noticed the red terminal on harness has one connection a bit melted. Cleaned all terminals dabbed on some dielectric grease. All connections seem great. My next guess is the IC ignitor. Any thoughts?

Are you pulling in the clutch when you push the starter button? Ed

Yes. All fuses check out fine.

You may want to test the clutch lever lockout switch and associated wiring to make sure it is completing the circuit when you pull in the clutch. If it isn't the starter button won't function. At one time I had a problem with the wiring on mine; the wires were worn where they pass across the handlebars. Ed

That checks out good too

Kill switch?
Steve

Well I checked visually for anything touching or crossed. Didn't test. I did test switch leg from switch to solenoid. Good there. No power on other contact. Looked at schematics and not really sure where the power source comes from to begin with. It connects to ignitor somehow. I'm guessing. Lol

Step back and figure the scematic out before replacing anything. The regulator/rectified and IC ignitor are in no way associated with power to the start switch. If I understand correctly, which I may or may not be, you can check with a meter and don't have 12v to the start switch? I don't have a wiring diagram to look at for the 81 model which I'm sure is slightly different, but on a 1980 KZ1000LTD looking at the wiring diagram, the way the starter gets powered is:
Battery power to a fuse, from the fuse to the ignition switch, when switched on goes to the kill switch, if it is in the run position, power to the starter button, when it is pressed power to the clutfh lockout switch, when clutch is pulled in power is sent to starter relay, the starter relay then has the 12v to pull the contacts together and power the starter. Good luck, following wiring diagrams can be very confusing and frustrating to say the least.

Makes sense. Certainly helpful. Thanks

You might check the connections in the ignition switch too.

Ive been busy sorting my loom out the last couple of weeks and 2 things that I checked and okayed were the fuse box and the ignition switch.
I later discovered that both were not ok. In each case one of the wires was connected by only a couple of strands and was covered in green fuzz. It was still connected,but only just. I didnt notice because the dodgy wire was buried under the other wires. So you need to pull all the wires up and away from the surface of the fusebox (and the ignition) and check that everything is hunky dory.
Opening and cleaning the inside of the ignition switch is very easy but be aware that there are 2 spring loaded ball bearings in the housing. Wrap a cloth around it as you open it or they may go flying off to 'Illneverfindthebuggersagain' land.

On a slight tangent, you should avoid using dielectric grease. It prevents contact.