1990 Yamaha TZR250

Some say that the 250cc two-stroke twins of the late 1980s and 1990s represent the pinnacle of racing machine technology. These 250cc racers were the real deal, with the factory-prepared versions offering peak power around 100bhp yet weighing not a lot more than 100kg. They were hard-core, and not for the faint-hearted.

The story of the TZR 250 goes back to 1973 with the first release of the TZ250, a production road racing motorcycle that had a wonderful, successful career winning multiple Japan Road Race Championships among other awards. Yamaha wanted to replicate a road-going bike as best they could using the racing model as their foundation for design and engineering ideas. 

Thus, the TZR250 was born, and production started in June 1986. The parallel-twin variant was named 2MA, and released in the UK. The 1KT model was the domestic Japanese model, and it was fitted with a more restrictive CDI to comply with Japanese laws which stipulated an upper limit of 45 hp for 250cc motorcycles. Lighting arrangements were also different, to comply with UK type approval regulations, particularly the indicators mounted on stalks rather than faired into the bodywork.

It evolved as a natural replacement for the popular RD 250/Yamaha RD350LC series of the 1980s. It has the Yamaha Power Valve System ‘YPVS’ which raises and lowers the exhaust port depending on the rpm of the engine. The YPVS servo motor starts to open at about 6,000rpm. In standard form it produced 45 hp due to the restrictive standard exhausts and ignition boxes.^[2]They were often raced against the Suzuki RGV250, which was known as having a slight power advantage over the TZR.

In 1989 the Yamaha TZR 250 got a redesign and the 3MA variant was born. The 3MA got a reverse cylinder design – the carb was in the front, and the exhaust was out of the rear of the cylinders. This in combination with revised timing bumped power up to about 50 horsepower. When restricted to the Japanese market, this bike made 45 horsepower.