Awesome shots!! But I like more the last picture...Oopps! Hold on! You might fall! lol I was astounded! Two thumps up, dude! Continue capturing BMX's moments with your friends.
Just a quick tip, I think these would really pop more if you shot with some fill flash. It would soften up all of the harsh shadows. Like #3 in your second set. I'd love to be able to see the face he's making better.