Looks like you were trying to freeze the bike and blur the background by panning with the bike and didn't quite pull it off.
Tim:
Thanks for the comment. I do not mind a little bit of blur when I try these pan shots out as I think it helps convey the sense of movement. Ideally yes, maybe the bike/biker being sharp would really make the photo pop. That photograph has been my most successful attempt at this type of image (so far). A far cry better than this early attempt from 2006:
[attachment=12168:Exploding_Train.jpg]
Mind you that train was booking at 100 kmh+ and my shutter was set to 1/30 sec.
p.s. (off-topic) Looking at the colour renditions of both my original photo and this "bonus" photo when I double click them from the LL forums, the colour is quite changed from how they look on my monitor. The oranges, reds, yellows are quite faded on these versions compared to the same jpeg photo when opened direct off my PC.
[Edit - replaced photo with sRGB version as per Julie's advice - Thanks]