I have about 20+ hours on a '03 CRF450F. I sold the YZ250F and couldn't be happier except for one problem. I have the suspension dialed in perfect except for severe head shake on braking and acceleration bumps. It is worse on braking bumps. The bike is stock except for a 52 tooth rear sprocket and Pro Taper bars. Anyone else experience this and find a cure? The only other complaint is the clutch lever rattles to no end! Thanks in advance.