Kawasaki has unveiled its 2021 KX motocross range headlined by an all-new 2021 KX250 boasting electric start and a hydraulic clutch.
The launch of the 2021 Kawasaki KX range also sees the championship-winning KX450 receive several small upgrades to the engine.
New for 2021
2021 KX250
– Electric start
– New hydraulic clutch offers a more direct feel and lighter lever action. Less play as the clutch heats up during heavy use results in more consistent feeling.
– The 2021 KX250 builds on the engine changes from the previous year to deliver even greater power and an even higher rev limit, plus electric start and a hydraulic clutch.
– Additional engine updates increase peak power by approximately 1.0 kW (1.4 PS). Rev limit increases a further 350 min-1.
– A new frame based on that of the KX450 contributes to improved handling.
– All-new KX450-style bodywork features long, smooth surfaces and a flatter tank-seat line.
– KX450-based frame (an evolution of the current design) and KX450 swingarm offer claimed improved handling and increased rear wheel traction.
– Updated suspension settings contribute to increased bump absorption and traction, while minor brake component revisions enhance controllability.
2021 KX250 Engine Updates
– Revised processing for the throats of the intake and exhaust ports (IN: revised angle, larger diameter; EX: larger diameter) contributes to the increased performance.
– Revised exhaust cam timing (retarded 3°) contributes to the engine’s increased performance.
– Valve springs feature a higher spring rate to match the higher rev limit.
– Revised combustion chamber design and a flatter piston crown contribute to the increased performance.
– Connecting rod is 3 mm longer. The decreased lateral force on the cylinder walls as the piston moves up and down helps to reduced mechanical loss. (Cylinder height increased accordingly.)
– Revised crankshaft web design offers reduced weight.
– Revised pressure balance inside the crankcase contributes to the increased performance.
– The use of coned-disc springs contributes to lighter clutch actuation when the lever has been pulled in, and a wider clutch engagement range, which facilitates control (especially when half-clutching). Friction plates with offset (slightly rotated) segments promote clean separation of the discs and help to reduce drag when the clutch is pulled in. The clutch’s slave cylinder is common with that of the KX450.
– Axle spacing revised in order to strengthen the transmission to match the increased engine output. Along with matching the revised axle spacing, shape-optimised gears contribute to weight reduction.
– Starting is electric only, via a button located at the right grip.
– Lightweight, compact Li-ion battery helps keep weight to a minimum.
2021 KX250 Chassis
– The new frame is designed for a better overall rigidity balance. While many parts are common with the KX450’s frame, the cast parts (like the shock tower mount and engine hangers) were designed specifically for the needs of the KX250.
– Engine is used as a stressed member, contributing to the frame’s rigidity balance.
– Steering head area with optimised rigidity, main frame rails with revised cross-sections, and a revised line for the swingarm brackets contribute to the overall rigidity balance. Wider lower frame rails also contribute to overall rigidity balance.
– KX450 swingarm delivers the rigidity to match the frame, and contributes to increased rear traction.
– Lower triple-clamp with revised rigidity reduces weight while contributing to the front’s ability to absorb bumps.
– Revised linkage ratios (same as those used on the KX450) contribute to both increased absorption and damping performance.
– Front and rear suspension settings fine-tuned to match the new frame contribute to increased bump absorption performance as well as increased traction.
Brakes
– KX450 front master cylinder adds to the high level of control and overall feedback from front brake.
– A smaller-diameter rear disc (ø250 mm >> ø240 mm) offers performance optimised for the KX250, contributing to controllability.
Body
– Bodywork designed to facilitate rider movement features long, smooth surfaces that make it easy to slide back and forth.
– Revised design for the top of the fuel tank top allows an even flatter progression from the seat to the tank. The flatter design gives the rider greater freedom of movement when changing
riding position, and facilitates sitting farther forward.
– Slimmer shrouds are positioned closer to the frame. Designed to be slim where they come in contact with the rider’s legs, the new single- piece shrouds facilitate grip.
– Smooth engine covers were also designed not to impede rider movement.
KX250 RRP $11,499
KX450
Completely revised in 2019 with a new engine mounted in its leanest chassis to date, the KX450 receives a number of updates in 2021 to maintain its edge in an extremely competitive class.
Engine
– A dry film lubricant coating on the piston skirt reduces friction between the piston and cylinder wall, contributing to increased performance.
– Revised construction for the hydraulic clutch includes replacing the clutch’s coil spring with coned-disc springs. The result is lighter clutch actuation when the lever has been pulled in, and a wider clutch engagement range, which facilitates control (especially when half-clutching)
– Increased clutch capacity care of larger diameter clutch plates (ø139 mm >> ø146 mm), and revised friction material contribute to increased fade resistance. Friction plates with offset (slightly rotated) segments promote clean separation of the discs and help to reduce drag when the clutch is pulled in.
KX450 RRP $11,999
The launch of the 2021 Kawasaki KX range also welcomes two completely new cross-country models, the KX250XC and KX450XC.
2021 KX and models are due to into Australia in the 3rd quarter of the year.