sorrie guys, but what do you all mean by buckling?

well anywayz i know it is okay under 3k rpm, but it gets kinda slower upto 4k rpm...and then the nasty rev hang around 4.5k-5.5k rpm.... i showed this to my brother and he was like wtf???? you dont have reflash to fix this??? lol oh btw he owns a ITR and his is AWESOME