Congratulations on placing this well in your first challenge. I saw the color version of your photo and it is spectacular!! I suspect you would have done even better with that one. Looking forward to seeing more of your work.
Incredible capture, definetely conveying power. I am not sure of the reason to show this in B&W, unless the biker and bike are predominantly black, I still would like to see it in full color. Also, using a fill flash may have improved the image further, assuming that you were using a wide angle lens and that you were not too far from the subject (8)