Engine wise the most noteworthy change is the adoption of a dry film lubricant coating on the piston skirt which reduces friction between the piston and cylinder wall and contributes to increased performance
A highly praised feature when introduced, the KX450 hydraulic clutch has been refined for the new season and two changes occur to aid rider feel and clutch life under harsh racing conditions.
In order to deliver a lighter clutch actuation when the lever has been pulled in, and a wider clutch engagement range, the traditional coil spring arrangement has been replaced by coned-disc springs. The resultant feel and control is evident in operation and, especially so, when half-clutching.
In the same area, Kawasaki engineers have revised both the friction material of the clutch fiber plates and the size of the driven, steel plates. Driven plates move up in size from ø139 mm >> ø146 mm while a new friction material contributes to increased fade resistance. Additionally new offset (slightly rotated) segments promote clean separation of the discs and help to reduce drag when the clutch is pulled in.
Finally, in terms of changes, a Renthal Fatbar is now part of the standard KX450 specification. With a ø28.6mm tube diameter, the all-aluminium bar helps reduce vibration and shocks transmitted to the rider while a 19mm lower grip position that is 8mm closer to the rider makes it easier for the rider to weight the front wheel.
The difference between and win and second is sometimes a hundredth of a second. Likewise a race winning package is defined by a specification created by a myriad of features. Now, for 2021, the KX450 package is the most complete ever – fact.