Professional motorcross racer Neil Hudson won the 1981 250cc premier championship organized by what group?
Neil Hudson:  He won the 1981 250cc Motocross World Championship. Motocross World Championship: FIM Motocross World Championship is the premier championship of motocross racing, organized by the Fédération Internationale de Motocyclisme (FIM), currently divided into two distinct classes: MX1 and MX2.
Fédération Internationale de Motocyclisme