Racing Bikes

Hi
Heres a couple of shots taken last sunday at the Caribbean motorcycle circuit.
Nikon D100 with a Nikon 70-200 f2.8 AFS VR lens and TC14EII.

I was hoping we'd get some motorcycle photographers in here. Motorcycle roadracing is what got me into sports photography.

Why are these so jaggy and pixelated? Did you crop a ton?

Thanks!
The original file looks very sharp, I guess I need to improve in my post procesing skills. :)
Any way, I do have some other motorcycle racing shots I post up soon.