The Yamaha YZ450F won the AMA Supercross Championship two years in a row, in 2008 with Chad Reed, and 2009 James Stewart. Yamaha was the first to build a production monoshock motocross bike (1975 for 250 and 400, 1976 for 125) and one of the first to have a water-cooled motocross production bike (1977 in works bikes, 1981 in off-the-shelf bikes). Yamaha's first Motocross competition four-stroke bike, the YZ400F, won the 1998 USA outdoor national Championship with factory rider Doug Henry.