New to Photography and looking for Critique (Motorsports Action)

[bruuuuce]

I have recently (July) gotten the bug to shoot action shots of sports car and motorcycles. Before July I have never done any photography with more than an Iphone or a point and shoot so I am green as they come. I would like to post a few of my recent photos and ask and see what I can do better to make my shots better.

Thank you in advance.

Photos were taken with a Nikon D7000 with the Sigma 50-500 Lense.