2011 Kawasaki KX450F, Great Ride! - Did Somebody Say Motor In the 450 cubic centimeter motocross game, the only thing that matters to serious racers is top-tier performance and running up front. And for 2011, the best tool for the job is once again a lime green one Kawasaki s reworked and revised KX 450F. In this arena you can t stand still technically, which is why Kawasaki engineers scrutinized every system and component of the race-winning 2010 model and came up with a host of tweaks that ll have red, blue, orange and yellow wondering what hit em.