89 KZ1000P cutting out at high RPM

So, installed new igniter and cleaned mechanical advance and guess what......same problem. Have had enough, so am off to see a bike mechanic in the morning.

Does the bike have a kickstand switch? Sometimes that circuit causes flakey ignition problems exactly as you describe, and would make an electronic tach go crazy. If the kickstand switch gets flakey, or if vibration is actually making the kickstand move, it cuts out the ignition at certain RPMs.

And, of course, any other switch in the path can cause the same problem, like a flakey kill switch or ignition switch.

I don't actually see a kickstand switch on the one KZP diagram I have. It does show an electronic tach, though.

Also, did you do any maintenance of any kind just prior to the problem showing up? Changed oil? etc?

I wouldn't trust those mechanics since there are no "maps" in the ignition. They probably are not aware of how these old bikes work.

Isn’t it just crap in the main jets?

Loudhvx, you nailed it. Mechanic found the issue, which was two ignition wires that were supposed to go to a kickstand switch, but which had been removed and the wires just hand wound together. Well, the two wires had come apart and were both resting in the exhaust, which was causing the intermittent connection. Funny th8ng is that the two wires were part of the wiring harnes, but the factory wiring diagram does not show this circuit!

Wow, I almost didnt post the response since it seemed very unlikely. I wrote most of it before I could get a look at the diagram. Maybe someone installed a harness from another bike, or maybe just part of a harness.

I'm glad its working now. Thanks for the update.