1980 KZ 550 breaks-up at high revs

I have a 1980 KZ 550, it's almost October and I almost have it ready for the road. I have one last challenge to overcome. The carbs are clean and balanced. I have what appears to be an electrical issue. The KZ runs smooth at idle through mid range but breaks up at high revs. If anyone has been through this and could point me in the right direction, I may get to ride it before there's snow on the ground. Thanks in advance.

Not sure of your description "breaks up at high revs."....
Example: breaking up meaning popping, backfiring, missing, no power, falls on it's face in acceleration power etc...

Questions...

1) What modifications if any have been accomplished?
Electronic ignition update, pods, jets, exhaust, cam shafts etc...

2) Ideal voltage to the coils?

3) No intake vacuum leaks?

4) If still points & condenser, have you replaced or at least adjusted correctly?

Just a few things to start with....

First thoughts that came to mind are where your needle & main jets being off/clogged. But could be one or a combination of things listed above...

OMR

Mine used to break up at high rpms I had points I think you have electronic ing.My points were pitted and my timing advancer needed lubed. I also did the coil voltage mod . Solved my high rpm breakdown.Just my experence....OMR seemed to cover all the bases on this issue...

if it has an aftermarket pipe on it it may not be jetted correctly sounds like a lean miss fire to me.

Lean... Yup, same thoughts here TB...

Pete, when running at mid rpm range ~ 65mph for example.
Safety in mind (no cars behind you)... Release the throttle and let it snap back...

Does it pop out the exhaust meaning a popping pop-pop-pop sound out the exhaust?
If so, your most likely running lean.

If applicable, a change in your needle jet clip position and one jet size change in the mains for a richer operation.

First things first, insure all other ignition variables have been diagnosed/replaced/tweaked. Double check your valve clearances, ignition timing, replace points and condenser's... Narrow down the issue to the carbs for last...

Yes jetting is a pain in the ass so do this last.

Unfortunately, it will and can be a pain but a Necessary pain you must learn and go through as well.... Once you get this dialed in you'll feel the difference in response and accelerations.

Good luck and let us know what you come up with...

OMR

I would check the timing first and foremost and make sure everything is in good working order if you have points. My KZ wouldn't run worth a crap past 5k rpms, and I checked the timing only to find out it was set as retarded as it could go.