The motorcycle division of Yamaha was founded in 1955
and was headed by Genichi Kawakami.
Yamaha's initial product was a 125cc two-cycle, single cylinder motorcycle, the YA-1, which was a copy of the German DKW RT125.
The YA-1 was a competitive success at racing from the beginning, winning not only the 125cc class in the Mt. Fuji Ascent, but also sweeping the podium with first, second and third place in the All Japan Autobike Endurance Road Race that same year.
Early success in racing set the tone for Yamaha, as competition in many varieties of motorcycle racing has been a key endeavor of the company throughout its history
often fueled by a strong rivalry with Honda and other Japanese manufacturers.
Yamaha began competing internationally in 1956 when they entered the Catalina Grand Prix, again with the YA-1
at which they placed sixth.
The YA-1 was followed by the YA-2 of 1957, another 125cc two stroke, but with significantly improved frame and suspension.
The YD-1 of 1957 was a 250cc two-stroke twin cylinder motorcycle, resembling the YA-2, but with a larger and more powerful motor.
A performance version of this bike, the YDS-1 housed the 250cc two-stroke twin in a double downtube cradle frame and offered the first five-speed transmission in a Japanese motorcycle.
This period also saw Yamaha offer its first outboard marine engine.