This kind of sport is the hardest to shoot and get right. To get the drama involved you need to isolate the biker and the bike from the background which is not the case with some of these. You need detail in the bike and biker that does not blend into the background and you need the face of the biker. Exposure and lighting have severely limited the effectiveness of many of these shots despite the fact that they have great potential. Postprocessing would greatly improve some but it needs to be done before you post and if you don't know how to do it, you should allow others to show you how to edit your work.
skieur