Introduced in 1973 as Yamaha’s new quarter-liter production racer, this nameplate replaced the earlier air-cooled TD series and became one of the company’s most important competition motorcycles. It was built as a customer road racer rather than a street bike, giving privateers access to factory-style Grand Prix technology in a machine that could be purchased and raced. Over time, it became closely tied to Yamaha’s 250cc racing success and to the development flow between Yamaha’s factory Grand Prix program and its production racers.
The model evolved repeatedly across its long run. Early versions established the formula, and later updates brought major chassis and braking improvements, including the adoption of Monocross rear suspension and disc brakes. In the 1990s, Yamaha shifted the machine to a 90-degree V-twin layout, reflecting technology developed in its Grand Prix program and keeping the racer competitive as two-stroke 250cc racing grew more specialized.
This was a true endurance nameplate rather than a short-lived homologation special: it remained in Yamaha’s racing lineup for decades and became a familiar sight in national and international paddocks. The final production run was the 2009 model year, after which production ended because of changing race regulations in the World Championship and related classes. As a result, the nameplate is remembered as one of the defining purpose-built customer racers of the two-stroke era, with a lineage that spans from the early 1970s through the end of the 2000s.