Kawasaki focused on further improving performance in the high-rpm and over-run ranges of the KX250F. How? By adding a new cylinder head with titanium valves, larger and smoother intake ports as well as a tapered titanium exhaust pipe that's 10-mm longer -- again to increase performance at high rpm.
Mechanical losses have been carefully dealt with by engineers to ensure that maximum power is transferred to the ground. Enhancements include:
· Lowering the amount of engine oil (1.0L instead of 1.5L) contributes to overall weight reduction;
· Changing the cam chain tensioner spring to one with a lower load reduces mechanical loss by approximately 30%;
· Revising ignition timing improves feeling at low-mid rpm.
The transmission of the new KX250F is also improved thanks to a new ratchet drive system (like that on the KX450F) in place of the gear-driven system of the previous model. The result is improved shift feeling. The clutch has not been overlooked either: lever ratios, spring rates and shaft locations were all reevaluated to deliver quicker, sharper gear shifts.
Common improvements and innovations
|2009 Kawasaki KX 250 F|
Both the Kawasaki KX450F and KX250F are built on the same new aluminum frame. Lighter yet more rigid than the old KX frame, it incorporates several key upgrades, such as:
· A 400-gram lighter swingarm;
· A finer, oval-shaped down tube allowing superior rigidity balance while reducing weight by 800 grams;
· Slimmer radiators for increased efficiency;
· Engine side covers made from synthetic materials;
· A narrower drive chain guide for a 100-gram weight reduction;
· A higher swingarm pivot for improved rear-wheel traction;
· New, wider footpegs offering increased grip and feel to the rider;
· And a larger synthetic skid plate for the engine, offering greater protection without increasing weight.
With such notable improvements to the chassis and a sizeable power increase, the 2009 Kawasaki KX450F and KX250F have all the ingredients to dominate their respective classes.Photo Credit : Kawasaki