Thoughts & advice

I was @ my local park today with a few mates who own radio controlled buggies!! these are the 1/5 scale large size around 20kg in weight 40-50mph and around 80cm long x 45cm wide so with that in mind i couldnt get to close.. using the 650d with kit lens on Tv mode...






there all similar in quality... if anyone could advise on how i can get sharper shots? Shutter speed on these where 1/640, also could it be the kit lens? all the above have been croppped a lot, as i couldnt get close enough without endangering myself... i would be gratefully off any help given thanks.