The Kawasaki KX250F was co-developed with the Suzuki Motor Co. under their unique joint venture that started in 2002. This joint venture produced the Suzuki RMZ250 which is the mechanical twin to the KX250F but is in yellow Suzuki markings. The first year of the KX250F was 2004 and it saw immediate success in Supercross and Motocross racing capturing the Triple-Crown of Motocross ( the East/West SX championships as well as the national MX title). However, the bike had some first year issues such as cooling and ignition problems. The 2005 version rectified these problems.
For the 2006 model year, Kawasaki took its own separate route in 250F development by releasing an all new bike that had no ties with Suzuki. The 2006 model features an all new aluminum perimeter frame, a heavily revised engine, new Showa front and rear suspensions, and Renthal handlebars. The new KX was very competitive, ranking highly in motocross magazine shootouts as well as in competition. In the 2008 the KX250F has been rated the number one 250F of the year. The 2007 KX450F was the top 450cc motocrosser in its class
For the 2006 model year, Kawasaki took its own separate route in 250F development by releasing an all new bike that had no ties with Suzuki. The 2006 model features an all new aluminum perimeter frame, a heavily revised engine, new Showa front and rear suspensions, and Renthal handlebars. The new KX was very competitive, ranking highly in motocross magazine shootouts as well as in competition. In the 2008 the KX250F has been rated the number one 250F of the year. The 2007 KX450F was the top 450cc motocrosser in its class
by Brianhogs February 2, 2008