I'm glad your subject is actually participating in the sport and it's not just a snapshot of someone on a bike. You almost nailed this one. The white lines make a great frame, but the square picture makes it look like he's going nowhere. This would have been much better if you could have stretched out the front end and moved the biker back a little. You need to give the impression that he has some place to go or someone to catch.
I wish I could see some background scenery or something to help emphasize the speed in this photo. With it just being the racer and road, it ends up looking more like a still shot, even though I know it's not. Something to add perspective would make this a more energetic photo, IMO.