Rennie Scaysbrook | June 18, 2019
The 2020 Kawasaki KX250 comes to the market completely revised, with the aim of increased top-end power, better handling thanks to new KYB suspension, and a new, stiffer chassis.
A completely revised KX250 will headline Kawasaki’s 2020 motocross line-up.
Below is what Kawasaki has to say about its new 250 charger.
ENGINE
- NEW engine with increased peak power
- NEW revised bore and stroke
- NEW finger-follower valve actuation
- NEW larger-diameter intake and exhaust valves
- NEW larger-bore high-performance piston
- NEW low-friction crankshaft pin plain bearings
- NEW stronger cam chain and relocated cam chain tensioner
- NEW shorter intake funnel
- NEW larger throttle body
- NEW shorter exhaust system design
Wider bore = more air = more power.
Acclaimed for its high output and smooth power delivery, the KX250 features a new engine with improved power, an even more potent high rpm range and a higher rev limit. Tuned to best suit race-experienced riders, the 249cc liquid-cooled, four-stroke engine focuses on more top-end rev thanks to improvements by Kawasaki’s factory racing efforts. The new engine features a revised bore and stroke that measures 78.0 x 52.2 mm. The wider bore enables the use of larger intake and exhaust valves and provides greater flow for high rpm performance.
The new piston design is ripped straight from the factory KX250 racers.
Like the design found on the KX™450 motorcycle, the KX250 now utilizes the finger-follower valve actuation – a valve train designed by Kawasaki’s World Superbike engineers. This design increases the rev limit and allows for the use of more aggressive cam profiles, which contributes to high rpm performance. The change to finger-follower valve actuation reduces the valve train mass compared to a tappet-style actuation. A diamond-like carbon coating on the finger followers helps protect against wear. Complementing the more aggressive cams are larger-diameter intake and exhaust valves with increased lift, flowing more air and contributing to improved power. Straighter intake ports contribute to increased intake efficiency. The new cams benefit from a thin and highly durable gas soft-nitride treatment to reduce wear and increase high rpm reliability. Lightweight titanium valves reduce reciprocating weight and offer high rpm reliability. The cylinder is offset 3 mm forward, reducing mechanical loss and increasing engine performance. Further increasing reliability is a stronger cam chain and relocation of the cam chain tensioner to the cylinder head, which offsets the increased loads from the more aggressive camshafts and higher revving engine.
New finger followers (in green) for valve actuation are inspired by the Kawasaki WorldSBK racer.
A plateau honing process of the cylinder bore results in a smooth surface with good oil-retention. The smooth surface also helps to reduce mechanical loss and improve power. A new, larger-bore, high-performance piston features the same design used by Kawasaki’s factory racers and contributes strong performance at all rpm. A short skirt, reinforced external ribs and the use of a bridged-box piston, featuring internal bracing, allow for a lightweight and strong piston design. The piston’s revised crown design helps achieve the engine’s higher compression ratio, while a dry film lubricant coating on the piston skirts reduces friction at low rpm and helps with the piston bedding-in process. To reduce mechanical loss and lift overall performance, the crankshaft pin has been fitted with new low-friction plain bearings.
New top-end power is clear to see here.
The airbox construction has been revised and features a shorter, tapered intake funnel, contributing to increased high rpm performance. The KX250 remains the only production motocross bike with dual injectors, an injector downstream of the throttle valve that is tasked with delivering a smooth, instant response, and a second, upstream injector located close to the airbox for a significant contribution to engine output at high rpm. The exhaust system length has been shortened to help increase high rpm performance and the hydro-formed joint pipe now features a reverse taper design.
Kawasaki’s new revised airbox layout.
A larger throttle body flows a greater volume of air and provides a boost in high rpm performance. Adding to Kawasaki’s engineering efforts for increased airflow is the repositioning of the intake duct for an even straighter approach for intake air. The downdraft-style intake routing increases the intake air’s approach angle into the cylinder, improving cylinder-filling efficiency and increasing the engine’s power.
DFI® COUPLERS
Contributing to the race-winning engine characteristics, the digital fuel injection system of the KX250 features a coupler package that has set the industry standard. Each KX250 motorcycle comes standard with three different couplers, easily allowing riders to select pre-programmed fuel injection and ignition mapping to suit their riding style or track conditions. The four-pin DFI® couplers select maps that are designed for standard, hard or soft terrain settings. Changing the engine map is as simple as connecting the coupler cap of choice. For riders looking to fine tune their ECU settings, the KX FI Calibration Kit (Handheld) is offered as a Kawasaki Genuine Accessory, and provides access to the fully programmable ECU. The handheld device eliminates the need for a trackside laptop and gives riders the ability to create custom maps for precise adjustment of fuel and ignition settings. The user-friendly device can store up to seven preset maps and is PC-compatible.
LAUNCH CONTROL
The launch control system of the KX250 motorcycle is a major advantage and favorite for riders who are focused on getting to the first turn ahead of their competition. The push-button activation retards ignition timing in first and second gear, helping maximize traction on slippery surfaces like concrete starting pads and put the bike’s potent power to the ground. Once the rider shifts into third gear, normal ignition mapping immediately resumes and full power is restored.
CHASSIS
- NEW lower front engine mounts
The new frame is much stiffer than in 2019.
The slim aluminum perimeter frame uses a lightweight construction composed of forged, extruded and cast parts that contribute to light, nimble handling. Thanks to new lower front engine mounts, changing from a through bolt to stud bolts at the front of the crankcase, the overall frame rigidity has been revised with improved ability to absorb bumps. The center of gravity and key dimensions such as swingarm pivot, output sprocket and rear axle locations have all been carefully selected so that the rear tire drives the bike forward.
SUSPENSION & BRAKES
- NEW 48 mm KYB coil-spring fork
- NEW KYB shock unit complements front fork
- NEW Uni-Trak® rear suspension link
- NEW stiffer front and rear spring rates
- NEW revised front brake pad material
- NEW larger-diameter 250 mm rear disc
- NEW rear brake master cylinder
The suspension is all new on the KX250.
For 2020, the KX250 is equipped with new large diameter 48 mm KYB inverted coil-spring front forks that offer improved action at the initial part of the fork stroke. The forks feature large-diameter inner tubes, enabling the use of 25 mm damping pistons and delivering smooth action and firm damping. A Kashima Coat on the forks’ outer tubes creates a hard, low-friction surface to help prevent wear abrasion on the inside of the tubes, ensuring the sliding surfaces remain smooth over time, while protecting the outside against corrosion. The lubricating material in the coat contributes to smoother suspension action and a better overall ride feel.
On the rear, a new KYB shock unit complements the new front fork. The rear shock features dual compression adjustability, which allows high-speed and low-speed damping to be tuned separately. Kashima Coat on the tank cylinder helps prevent wear abrasion and reduces friction for smoother suspension action. A new Uni-Trak® rear suspension system mounts the suspension arm below the swingarm, allowing a longer rear suspension stroke. The longer stroke allows for more precise suspension tuning. In order to match the KX250’s more powerful engine, the front forks and rear shock feature stiffer overall spring rates.
The 25 mm damping pistons help deliver a smooth suspension action and firm damping.
Contributing to the numerous factory-style racing components on the KX250 motorcycle are petal disc brakes. Up front is an oversized 270 mm Braking® brand rotor, which delivers strong braking force and superb control. A revised front brake pad material, like that found on the KX450, delivers linear brake force application, helping to facilitate control.
On the rear, a new larger-diameter 250 mm Braking brand disc contributes to stronger stopping power, complementing the large front disc. A lighter rear brake master cylinder, like those found on the KX450 motorcycle, powers the larger disc. The petal-style discs contribute to both sporty looks and help deflect debris. A rear caliper guard helps protect the caliper from damage.
ERGO-FIT® Adjustable Components
Kawasaki continues its unmatched commitment towards providing riders with class-leading comfort thanks to its ERGO-FIT® adjustable handlebar mounting system and footpegs to fit a variety of riders and riding styles. The handlebars feature four-way adjustable mounts. The multi-position handlebars offer two mounting holes with 35 mm of adjustability, and the 180-degree offset clamps boast four individual settings to suit different size riders. The footpegs feature dual-position mounting points, with a lower position that reduces the standard setting by an additional 5 mm. The lower position effectively lowers the center of gravity when standing, and reduces knee angle when taller riders are seated.
BODYWORK & SEAT
- NEW factory-inspired green bodywork
Complementing the improved power and precise handling of the KX250 is minimalistic bodywork that includes slim radiator shrouds for an aggressive race-ready look. A flat fuel tank and seat design help to aid in a more seamless design, making it easy for riders to move around on top of the bike.
For 2020, the number plates and airbox of the KX250 motorcycle have been updated to the color green, resembling the same look found on the bikes used by the factory racing team. The front and rear fenders and fork guards implement a sharp design that makes the bike look more compact. Adding to the distinctive Kawasaki factory race team look is a green oil cap, generator cover plugs, green alumite suspension adjusters and black alumite rims.
KAWASAKI KX™250
Color: Lime Green
MSRP: $7,799
Availability: Now
