The model was launched in 1974, and has been regularly updated and is still in production with new releases every year.

The air-cooled motor was replaced in 1982 with a 249 cc liquid-cooled two-stroke reed-valved engine with a mechanical, rather than servo-driven, YPVS exhaust valve for a wider spread of power.

Although other makes of contemporaneous motocross engines featured theoretically superior crankcase reed-valves, the YZ250 still has the reed-block integral to the cylinder.

[1] A large range of after-market tuning parts are available, owing to the bike's design being fundamentally unchanged since 1999 and the sheer numbers sold over the last fifty years.

[2] In the 2005 model year, the YZ250 gained a new frame made from aluminum that reduced the dry weight to approximately 212 lb (96 kg).