The Yamaha RD250 (known as the RZ250 in Japanese and Australian markets) is a parallel twin cylinder two-stroke motorcycle produced in Japan by the Yamaha Corporation from 1973 to 1987.
The air-cooled models were produced from 1973 up until 1979. From 1980 until 1987, liquid cooled versions were produced, named the RD250LC, RD250LC-II and RD250 YPVS.
References
Yamaha RD250 Wikipedia(Text) CC BY-SA