have to say they all look either slightly blurred or out of focus...
#1 - rider is too central too the shot and there is little context of what the jump looks like..if riders are trying to whip off a jump, get in front and as low as possible, and back far enough to get the jump in...
#2 - TREE !...:bang:..looks like he's about to meet his maker!!! again from the side, rider central to the shot and little of the jump
#3, #4, #6 - ditto central rider, no context
#5 - pic of the bunch, would have been better straight on
if you want motion blur, then go side on with the rider and slow your shutter speed down, stand further away so you don't have to pan so fast....slow panning over jumps is especially hard as you have both vertical and horizontal movement...
get yourself along to aston hill, porc for one of their comp days...is a top day out
look forward to your next set..
JB