I literally discovered Valley Dirt Riders on the way to another shoot. It was a half day gig, so I stopped in and grabbed these shots in the afternoon. Shot on my FS700 mostly at 240fps, with one shot at 120fps. For post, I used this as my first foray in to Premiere Pro CS6 and SpeedGrade.
Full technical details on camera settings and post workflow are at: http://www.jeffcrowell.net/motocross-at-240fps/