KZ650 won't rev past 6,000RPM after rejetting

Just put new main and pilot jets in my 81 KZ650 CSR. Previously with stock everything except for pod filters, I was able to get it to run fine with the air mix screws backed out 7/8 of a turn on all four. Decided to up the sizes of my jets slightly so I could allow more air in--in hopes she'd run better. Went up to 17.5 pilots, 107.5 mains. I believe the stock jets were 15 pilot and 102.5 mains.

Anyways, it started right up, runs great up to about half throttle, but it won't get past 6,000 RPM. Backed my air mix screws out to 1 full turn. Not sure if it's running rich or lean once it gets up there. Any thoughts?

I'm running 105 mains with the needle in position 2 on my 78 kz650.
I have pods and a 4-1 exhaust. I also have air corrector jets. air corrector jets

What do the plugs look like

www.dragstuff.com/techarticles/how-to-read-plugs.html

Adding fuel does not always mean better performance.

These are not your bike specific but read them over it will give you basic carburetor function. Your comment on upping the main jet to allow more air in leads me to think you need a better understanding of how a basic carb functions.