He was killed in an accident during tyre testing for Dunlop at Okayama International Circuit in Japan.
He got a wild card ride in both the 1995 and 1996 Japanese Grand Prix and while a non-finisher in 1995, rode an impressive race in 1996 to finish 2nd behind then 250cc World Champion Max Biaggi.
In 1999, Numata had a one-off ride on the Muz 500 as a replacement rider for Luca Cadalora in the 500cc class, finishing 13th in the race.
Numata, like many of the top Japanese riders, was also a regular competitor in the Suzuka 8 Hours Endurance race.
He competed in the event on seven occasions between 1991 and 2002, his best finish being a 4th place in 1993 partnered with Akira Yanagawa.