[img]http://d.yimg.com/a/p/ap/20100829/capt.c4e0a3bc0a14447abb68204bfde16caa-c4e0a3bc0a14447abb68204bfde16caa-0.jpg?x=130&y=78&q=85&sig=996zX75MUJOYuWnPcy6zZg--[/img]AP - The death of a 13-year-old motorcycle rider at Indianapolis Motor Speedway cast a shadow over Sunday's races at the historic track and prompted mourning competitors to defend the development system for the dangerous circuit.