The Yamaha TZR250 is a motorcycle manufactured and produced by the Japanese motorcycle manufacturer Yamaha between 1986 and 1996. Yamaha produced the road going two-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/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 50 bhp is claimed at 10,000rpm. Although mid 40s is more realistic, and will not rev much above 9,500rpm in standard trim, owing to the restrictive standard exhausts and ignition boxes.