Yamaha Tzr

The Yamaha TZR250 is motorcycle manufactured and produced by the Japanese motorcycle manufacturer Yamaha between 1986 and 1999.
Yamaha produced road going 2-stroke motorcycle, loosely based on the TZ250 Yamaha racing bike. Parallel-twin, reverse cylinder and finally V-twin variants were produced. It evolved as a natural replacement for the popular RD 250/350 LC series of the 1980s. It has 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 50 bhp is claimed at 10,000rpm. Although mid 40's is more realistic, and will not rev much above 9,500rpm in standard trim owing to the restrictive standard exhausts and ignition boxes.

Racing

Still raced in the Yamaha Past Masters race series with the British racing club - BMCRC. Racing engines currently claiming circa 56 bhp @ 11,000rpm. Racing pre-mix fuel ratios typically 1:30. Standard exhausts are difficult to improve on in terms of power and torque, but they are very heavy and impede ground clearance. Jolly Moto exhausts are popular replacements as they are lighter, produce similar performance, and allow better ground clearance.
In 1987 Mat Oxley was the first person to lap the Isle of Man TT course at over 100 mph, riding this model. An F3 racing kit was produced for a few years which included ignition boxes, carbs and exhaust pipes, helping increase maximum revs, power and torque.

History

Production started in June 1986. At a cost of around $6,000 new on release it was seen as an expensive bike for a 250 cc, but given that places such as Japan and Australia had 250 licencing laws in place one can imagine the stir that something that could hassle 750's on a track caused. 2MA variant being the UK variant and the 1KT model being the domestic Japanese variant. Variations between these two models being minimal, e.g. wording on the brake master cylinder in English or Japanese. Lighting arrangements were also different, to comply with UK type approval regulations, particularly the indicators were mounted on stalks rather than faired into the bodywork.
Then came the reverse cylinder version 3MA, then the V-twins 3XV. The variants followed the configuration of motor of the racing TZ250 of the time. Manufacture of TZR250s stopped in 1996.