The year 1972 was a good one for Yamaha, which, in its second season of works participation in motocross Grand Prix, finished second in the 250cc class with Hakan Andersson and fifth in the 500 class with Van Velthoven, while the YZ250 of Gary Jones won the AMA championship.
Yamaha's great strength is its speed of reaction. The 1973 MX privateer's machine was a genuine replica of the 1972 works machines. The cycle part was completely redesigned, with the engine set lower in a new double cradle frame, while the rear shockers introduced a separate hydraulic fluid tank with external adjustment of the damping. This marked the beginning of a trend towards ever greater sophistication of suspension systems. It was underlined at Yamaha by the introduction of cantilever rear suspension in 1973.
The major revolution in two-stroke engine design, which was to bring automatic intake valves -first on the cylinder, then in the crankcase -and valves in the exhaust, still lay in the future, so the MX250/MX360 Yamahas of 1973 were somewhat lacking in flexibility. Yamaha was world 250cc motocross champion in 1973 with Hakan Andersson, while bikes entered by the French importer Sonauto won the national 125cc championship with Jallat riding and came second in the 500cc class, this time with Drobecq in the saddle.