This weekend marks the official debut of Kawasaki’s pre-production KX450F four-stroke motocrosser. It will be raced in the all-Japan 250 motocross championship series on April 11, 2004, with Tetsuya Mizoguchi aboard (last year’s 125 MX champion in Japan aboard the KX250F).
Kawasaki is being fairly stingy regarding specifics about this new machine. It does disclose the 449cc engine is a double overhead cam design, with four valves. Additionally, the engine is “housed in a semi-double cradle frame with a unique tapered box-section backbone tube.” The frame design is a departure from Kawasaki’s traditional steel perimeter frame design, utilized since 1990 in Kawasaki production motocrossers below 500cc. One could speculate that the height and width of the 450cc four-stroke single led Kawasaki to abandon a true perimeter frame, in order to keep the gas tank section of the bike narrow.
Kawasaki indicates additional information will be provided as the Japan motocross series progresses over the next few months. At this point, it appears Kawasaki is on track to introduce a production version of this machine for the 2005 model year (just as it did with the KX250F last year).
