+1. The pic above is awesome. Don't listen to the photo nazis...Great pics!
Some have mentioned increasing the shutter speed next time, I wouldn't recommend that unless you want it to look like the bike isn't moving at all. Depending on what you are going for, a faster shutter speed can work. It looks like your buddy went for the slower shutter speed for a more blurred background. Some pics will come out blurry with a slower shutter speed if you haven't practiced a lot at panning. Take the pic above for example, the rider and the middle of the bike is in focus while everything else is out of focus. If you want more of the bike in focus next time, keep the shutter speed the same, but increase the aperture up to around F8. This way more of the subject will be in focus while the background is still blurred and out focus. The pics still turned out great.