Classic Bikes Custom Bikes Individual Racing Bikes AJP AJS Aprilia Ariel Avinton / Wakan Bajaj Benelli Beta Bimota BMW Brough Superior BRP Cam-Am BSA Buell / EBR Bultaco Cagiva Campagna CCM CF Moto Combat Motors Derbi Deus Ducati Excelsior GASGAS Ghezzi Brian Gilera GIMA Harley Davidson Hero Highland Honda Horex Husaberg Husqvarna Hyosung Indian Jawa Kawasaki KTM KYMCO Laverda Lazareth Magni Maico Mash Matchless Mondial Moto Guzzi Moto Morini MV Agusta MZ / MuZ NCR Norton NSU Paton Peugeot Piaggio Revival Cycles Roland Sands Royal Enfield Sachs Sherco Sunbeam Suzuki SWM SYM Triumph TVS Ural Velocette Vespa Victory Vincent VOR Voxan Vyrus Walt Siegl Walz Wrenchmonkees Wunderlich XTR / Radical Yamaha Zero Video Technical
Complete Manufacturer List

Yamaha YZR 500

1974

The Yamaha raced the YZR 500 since 1973 - for 30 years over 28 generations. Till 2002 20 different riders won 115 races for Yamaha, and also won 11 world championships and 9 constructor's championships with the YZR.

Late in 1972 there was talk that Yamaha would enter a new motorcycle in 500-class racing, developed from putting together a pair of two-cylinder 250-cc. engines. It was to be raced by the Finn Jarno Saarinen and the Japanese Hideo Kanaya.
The talk proved to be anything but idle. At the 1973 French Grand Prix, Saarinen rode the new four-cylinder Yamaha to first place in the 500 class, roundly beating Phil Read's MV.

After showing that he had the right skills and the right motorcycle to win the world championship, Saarinen lost his life at Monza, and Yamaha, as an act of mourning, withdrew its team from the 1973 championship.

Yamaha hired Giacomo Agostini and went back into 500-class racing in 1974. The Italian was given a motorcycle with several tuning defects and had some bad luck. In 1975 the motorcycle was completely rebuilt, and Agostini rode the Yamaha 500 to win the championship. At the end of the season the company announced its withdrawal from official racing, but it let Johnny Cecotto have a 500 model like Agostini's for the 1976 season. The absence of technical assistance and the unexpected development of the Suzuki RG 500 caused the Yamaha 500 to lose its title.

1975
Year	Model
1973	OW20: Liquid-cooled, inline-4, two-stroke engine, chromoly frame. Yamaha’s first 500cc factory bike won from the outset at the first round of the 1973 season, ridden by Jarno Saarinen.
1974	OW23: Yamaha’s first machine created specifically for 500cc racing. Yamaha won their first 500cc constructor’s championship with it and in 1975 Giacomo Agostini rode the revised OW26 to a world championship as well as giving Yamaha their second 500cc constructor’s championship.
1976
1977	OW35: Changes were made to the valve intake system, stroke ratio, and carburator.
1977	OW35K: Introduction of Yamaha’s Power Valve System (YPVS). Kenny Roberts won his first of three championships with it.
1978
1979	OW45

1974

Yamaha YZR OW20

Motorcycle: Yamaha YZR 500 Manufacturer: Yamaha Motor Co. Ltd.,
Iwata Type: Racing Year: 1974
Engine: Yamaha four-cylinder in-line, two-stroke, with cross-port distribution and gill valves. Displacement 492.6 cc. (56 mm. x 50 mm.)
Cooling: Water
Transmission: Six-speed block
Power: 98 h.p. at 10,000 r.p.m.
Maximum speed: 175 m.p.h.
Chassis: Double cradle, continuous, tubular. Front, telescopic fork suspension; rear, cantilever telescopic suspension
Brakes: Front, double hydraulic disk; rear, single h ydraulic disk

1977

1978