2015 Kawasaki KX™250F, 2015 model year introduces a host of new updates designed to retain the crown as the most successful 250F on the market. - The 2015 model year introduces a host of new updates designed to retain the crown as the most successful 250F on the market. The record books don’t lie. Whether it’s Team Green amateur racing, professional AMA Supercross or Motocross, the most successful 250 cubic centimeter motocross bike in the 4-stroke category just got even better thanks to a series of upgrades designed to maximize the performance of this already impressive motorcycle.