Daijiro Kato
Eight Grand Prix motorcycle racing champions have died while racing or practicing in Grand Prix motorcycle racing: Dario Ambrosini in 1951, Leslie Graham in 1953, Rupert Hollaus in 1954, Tom Phillis in 1962, Bill Ivy in 1969, Jarno Saarinen in 1973, Daijiro Kato in 2003, and Marco Simoncelli in 2011. While Hollaus is often credited as the only rider to win the championship posthumously, he had mathematically clinched the 1954 125cc world championship title as he had achieved the maximum number of points possible at the time of his death.