I just watched it and noticed a couple things...
1. Some of the cuts could use a little work. Most were on beat, but a couple (look at 0:55) missed. As for the other cuts, some of them were a bit awkward. There are some shots that take too long to end. One example would be 1: 13. there is an awkward moment after the rider fall behind the knuckle. I'd rather watch more of them riding into the feature instead. Also look at 1:03, there was too much ride away for my taste.
2. Have you done any color correction yet? The whites were way out of line in a lot of those shots. Open up a videoscope and crank away to get your levels adjusted and your whites/blacks constant.
3. If you need to put that many logos into a video, don't do it all at once. If you want to do that though, let them sit for longer with a more stagnant background. That shot was just confusing.
4. Put in the names of the riders.
5. Are you going to do any more with sound? A lot of those shots did not involve much camera movement which means you should be able to get some decent sound out of them. If you add sound, it will draw viewers in so much more.
Good work though, I'm excited to start filming at Sunday River next season!