This deff requires a crop, had at first I know but you'll get used to it, my first football shots had to be forceable cropped several times before they showed the right picture.
You've done well with getting the bike sharper than the background which helps convay the sense of speed, and the stance of the rider as help with the action.
As Ade said try scouting different places out so you de-clutter the background, although at times this isn't possible so dont kill yourself in the process. Also play with angles and perception, if you know the sport then I am sure you can second guess where all the action will be, then find the obviouse shot and work to get something different. In the case of above I would have looked to get really low, removeing a lot of the background, retaining angry sky and action, crop as much with feet and zoom and then wait.
That said its a great start and it looks like you have an eye for getting yourself in the right place at the right time which can often be the most difficult part.
Keep it up I look forward to seeing more.