Predicting that the 4-stroke wave would soon reach the motocross world as well, Yamaha quickly got to work on developing a 4-stroke motocrosser. The result was the birth of the YZM400F Yamaha factory ...

However, concern for more environmentally friendly performance grew and 4-stroke engines are now the norm because they inherently have better fuel economy and less exhaust smoke. As of 2019, the only ...