kix500, what is your elevation? I had the same issue lacking top-end. But, ended up being a VERY rich mixture. You want some homework or experience? Go through the Jetting Again and again sticky. I had the same exact issue and went through 200+ posts to fix it. Now I walk anything in site and have since then added some nice goodies.
EDIT: Don't forget to read most. I ended up having to buy about 20 needles and 20 main jets/pilot jets. I came out with a 38 pilot (if I remember right) and a 155 main jet and some wierd ass needle. Buy carb parts from Sudco, they are $5 per needle rather than $30 from Kawasaki. Take time and read the thread. It will give you an idea and you can learn from our trial and errors. Good luck!
EDIT: EDIT: Toss that piece of metal crap called a flywheel weight if you want top-end. It doesn't hurt it bad, but doesn't help it either. Start with the obvious.