I see three different models of kawasaki 600 cc bikes for 97 Ninja ZX-6R Ninja ZX-6 Ninja 600R the zx-6r and zx-6 have the following rear shock Bottom-Link UNI-TRAK with remote reservoir, gas-charged shock, adjustable preload, 19-way compression and 4-way rebound damping the ninja 600r has the following rear shock Bottom-Link UNI-TRAK with air adjustable shock, 4-way rebound damping Todd- sorry about jumping on your advice, I searched zx600 and only saw the gas charged shock. If it is the 600R then it is air adjustable