Refined Power Delivery for Improved Holeshot Performance

A host of improvements make the 2008 Kawasaki KX™450F motocrosser easier to ride and more reliable than ever. A newly-revised powerplant and improved shifting highlight the improvements made to the dominant AMA and World Supercross GP Championship winner.

With little doubt about the ample power of the KX450F, the 2008 engine received smoother, more user-friendly and linear low-rpm throttle response and torque delivery. These changes result in reduced fatigue, allowing riders to go faster for more laps. The improvements were achieved with new wedge-shaped crank webs, combined with a new heavier flywheel, resulting in reduced engine vibration and better low-end performance. Reliability of the engine was enhanced via a new connecting rod material with a harder surface, a revised gear ratio and rotor on the oil pump for increased oil circulation and the piston-cooling oil jet was redesigned to prevent oil from being trapped under the piston.  

The bottom end changes are coupled with a new shift cam shape and a wider track on the shift drum to permit easier and more consistent gear selection in the KX450F’s five-speed transmission. An ultra-smooth coating on the intake ports improves intake efficiency and throttle response, while revised ignition data provides easier restarting and a new five-bolt oil pump cover round out the engine upgrades.

Already a great handling motorcycle, the 2008 KX450F further benefits from new engine mounts spaced 10mm farther from the engine. This allows a slight decrease in torsional frame rigidity making for quicker turning and increased rear wheel traction. 

Complementing the chassis change, the Kayaba fork and shock settings were fine-tuned to improve the front / rear balance for quicker turning and slightly stiffer settings were made to improve the bottoming characteristics. The overall suspension action is even smoother now through the addition of the friction-reducing Kashima Coat treatment on the inside surfaces of the outer fork tubes and the shock reservoir. 

The 2008 KX450F will be available in Kawasaki lime green, with new black alumite-coated rims for a factory appearance, and aggressive graphics