Found this on the Kawasaki Forum and thought it would prove useful on here.
Now some basic information regarding the bikes covered.
98/99 ZX6R "G" Model
00-02 ZX6R "J" Model
Now, for the most part, here are the differences comparing the "G" to "J" Model bikes.
-Upper Fairing only...
I've got an 07 zx6r that I don't ride so much anymore, won't spin past 12k rpm. I started it up this year and felt like it was dogged down. After playing with it I realized it runs pretty close to normal up to about 10k rpm, and loses all acceleration power. will very slowly spin up to 12k, and...