1975 Grand Prix motorcycle racing season

Season summary

1975 represented a changing of the guard in Grand Prix motorcycle racing, both for riders as well as machines. Giacomo Agostini would claim his final 500cc World Championship aboard a Yamaha two-stroke machine. This would also mark the first time a two-stroke machine had won the premier division.

Angel Nieto claimed his fourth world title for Kreidler in the 50cc class. In the 125cc division, the Morbidellis of Pileri and Bianchi dominated, finishing first and second in six of the ten events. Despite Michel Rougerie scoring more points, his Harley-Davidson team-mate Walter Villa would take the 250cc title because of the "best of six finishes" rule. A young Venezuelan, Johnny Cecotto claimed the 350cc title, becoming the youngest-ever World Champion at the age of 19.

In the premier division, MV Agusta with Phil Read aboard, refused to go down easily. The Championship was not resolved until the tenth and final round in Czechoslovakia, when Agostini emerged triumphant to claim his fifteenth world title and the first in the class for a two-stroke. Barry Sheene would also serve notice that he was an up and comer with victories at Assen and Sweden. The writing was on the wall for four-stroke machinery as eight of the top ten riders in the points standings were aboard two-stroke machines.