yo i dont know abot u guys but when i shift up from 4 to 5 the bikes lossess its guts and i i just resort to changing back to a4 but after some time thinking ive found out why check ure rear sprocket and see how small the **** is there u go thats ure prob im in the process of getting a renthal sprocket kit designed for the cr and put it on me bike once fitted ill let u know what the results are ben please feel free to e-mail me