I put my copyright in the corner but ensure it's large enough it can't be cropped without cutting into the subject - that seems to work!
Some nice shots there including some of my little mate Tai being given a run for his money for a change! Fairly noisy though - are you shooting without flash and using high ISO by any chance?
No three - Tai on the tac ride, and the final one, would be my firm favourites. Have they been sharpened at all> If not then might be worth trying that.
Excellent to see a bit more speedway stuff on here - not so long ago there was only me doing it!