No power above 6000rpm

I didn't want to make a thread but I'm at wits end and before I bring it to a mechanic I figured I'd ask you guys.

The bike is an 82 kz750 ltd, 4-1 Mac exhaust, stage 3 jetted and z1 pods.

The bike runs excellent up to about 6000rpm and then it cuts out. I don't believe it to be carb/pod related though I'm sure no one will agree with me. I say this because it did this well before I ever jetted or put pods on. In fact it's done this for the 4 months I've owned it.

What I have done: thoroughly cleaned carbs, replaced needles and carb gaskets, jetted and synced carbs with vacuum gauges. New plugs, cleaned stock wires. Lubed and inspected timing advancer, clear tube method inspecting float levels, cleaned all electrical connection with Emory cloth and electric cleaner

Is it ignition? Fuel? The plugs are dark and sooty but I'm not an expert at plug reading.

Well, you already know it is either fuel or electrical. Soot normally indicates fuel. Properly jetted the plugs should be tan.
Can you describe the jetting / tuning process? Like, did you install the main jets, do a plug chop and plug read, etc.?
I found that the Dynojet mains tend to be too big and I need to go down 2-3 sizes from what they ship.
If you need, I can find the website where they tell you how to do jetting/plug chops. Actually, I left a link in another thread here if you want me to find it for you.
Carb tuning link

I think i have it but link me if you dont mind. I do think the 136 jet they provide for stage 3 is too large but it did this same thing when I had the stock 125 jets. All I did was install the new needles, jets, drilled the slides and vacuum sync. Are you suggesting decrease the main jet down to the 130 or 126 the kit comes with and see what happens?

First, don't use the Mikuni jets, their numbers do not coincide with the Dynojet numbers. Start with the smallest size Dynojet main jet. Install fresh or clean plugs. Put the needle clip in the middle slot. Go for a WOT plug chop run.
Report back your results.
I placed the link in my previous post.

I don't have mikunis there keihin but I catch your drift. I'll try it out tomorrow and let's see why happens. I really thought it was/is ignition related.

As long as they are CV carbs the operation should be similar. You need:
Main jets
Adjustable needles
I figured you had the Keihins but the process is the same, tune the mains first, the needle second, then the float height.

The older VM style carbs tune the other way around, bottom up instead of top down.

It could still be ignition related, but the soot covered plugs indicate a rich condition versus a no-spark condition.

Are the original ignition coils, caps, and plug wires still fitted?

Is the original ignition still fitted?

What spark plugs are fitted (probably should not be "R" plugs)?

Good Fortune!

Patton wrote: Are the original ignition coils, caps, and plug wires still fitted?

Is the original ignition still fitted?

Good Fortune!

All original as far as I know. The reason I think ignition is the way I lose power. It literally sounds like its misfiring and cutting out. Almost like I'm taping rev limiter but I still have about 3000 rpm to go. I'm fairly new to motorcycles or anything carbureted really so I could be wrong.

An 82 would have an electronic ignition, would it not? Does it have a mechanical advance or is it in the ignitor?
All you have is the signal generator on the end of the crank, the ignitor, the coils and the plugs. Of course, you might want to check the wiring between each of the components.

Plugs are b8es. Non resistor version as the manual says

Old hard cracked plug wires may leak voltage.
And sometimes old resistor style plug caps may provide too much resistance.
Old ignition coil(s) might possibly have developed an internal short at higher rpms.

The Kawasaki dealership likely has an ignition coil electrotester that determines strength of the furnished spark under load at high rpm.

Good Fortune!