The sharpness and color is courtesy of my Nikon 70-200 f/2.8 and the often maligned D7000. The tighter shot was 1/320s and the other was 1/125s both at ISO 200.
I gave the lighting lots of consideration and based where I stood on both the position of the sun and that I wanted to catch the bikes with the riders leaned towards me. I think it makes a much better shot than when they are leaned in the other direction.
These are fantastic imo. Great action and as far as I can make out the panning is spot on. Great background blur, motion blur on the wheels yet the subjects are pin sharp and beautifully exposed. Yeah, fantastic shooting.
Side note: the little 250's sound awesome revving up around 14k rpm and they handle like a dream. I would love to have one of those to ride around the backroads here or the twisties in and around Tennessee.
Just because of my personal bias towards the MotoGP class, I didn't pay as much attention to the shots that I have from the other classes. I looked in the folder these came from and see there are probably several more that are worth posting. Based on your encouragement, I'll sit down (probably this weekend) and find a few more.