I voted for number 2. I might have cropped just a tad looser on the sides, but I always like getting in close on the rider and bike. They're both great, but I like seeing the little details you pick up when stuff is cropped a little tighter like the second shot.
1 - fits very nicely on the pc screen (like for a screen background), has a nice clean background (doesn't get much cleaner, LOL), this version would be good for more of a track website shot or something for the track.
2 - great rider shot for the rider like to print & frame, see more detail/larger image of rider in the sizes you posted, good for like a mag article featuring the rider, and I tend to crop to the rider similar to this in my own mag/web shots.
I like the second one better as it fills up the pic.The first one is good tho as it is in the "one third" of the frame. I would have to say its preference over talent. You are getting really good Okie,you better be careful you might have found another career.
I voted for the first one because I like a bit of space. I also like how the bike/rider is further to the right, leaving space to the left for him to ride into.
As far as other things go, that shot looks exposed perfectly. There is still detail in the black, and the whites are barley blown at all. The only thing to make that shot any better is to add 3000 people behind him cheering him on.
I picked the second one for 2 reasons.
1) The tighter crop makes the effect that there is more action in the shot. With the first crop, the action was all to one side and the left side was kind of empty.
2) The second crop has a bit more detail due to the extra size because of the cropping I am guessing.
If he had been a bit further into the corner, taking up more of the picture, I probably would have picked the first one.