With the introduction of the revolutionary four stroke YZM400F factory prototype in 1997 Yamaha changed off-road motorcycle sport as few other manufacturers have ever achieved before. The YZM400F brought four stroke power and traction in an agile two-stroke type of chassis to the race track, a concept that in the end proved to be more competitive then the commonly used two-stroke machines of that era.

The initial stones in the YZ ‘wall’ of superiority were laid in 1998 when Doug Henry took the YZ400F to a thrilling debut in the AMA-MX championship, winning five nationals on the way to the crown. He also gained four podiums within the Supercross campaign of that year.

In 1999, Andrea Bartolini won the machine's first Rider’s World Championship in the 500cc class with the production based YZ400FM, and ever since that time Yamaha have led the four-stroke revolution. The bike has formed the basis of winning technology in MXGP, MX1, MX3 and AMA Supercross and AMA Nationals since the turn of the century.

The main innovations of the production YZ450F for 2008 involve a new aluminium frame with altered geometry, making the base for Yamaha Factory Team’s machinery extremely competitive straight from the crate. In essence the team only needs to tailor the production bike to suit the riders' specific styles.