When I shift it sounds like i'm missing the gear but i know im not. I have a 2005 zzr 600. Is it rider error or should i run it at a high rev? or tranny/gear problems? Any help would be awesome!!  

try changing the oil and then adjust the shifter and then just listen for the high pitch and stift  

First before you do anything,change your oil to Mobile 1 synthetic 15w50. trust me I own a 07 ZX14 with the same problem with the tranny. After the mobile 1 change,,,no more problem. Also purchase a Mobile 1 oil filter for it. if your ZZR600 was a girl,,,she'd kiss you. you don't need to run it at a high rev it's a Kawasaki not a Suzpukey.