The Yamaha YZ250F is a motocross motorcycle first released in 2001 by Yamaha. It had a five-valve, DOHC, four-stroke engine and initially had a steel frame and an aluminum subframe, which was replaced in the 2006 model with an all-aluminum frame.
This combination leads to the YZ250F being praised for combining the broad-power characteristics of a four-stroke engine with the light handling more common in smaller, 125 cc two-stroke motorcycles.