Kawasaki KX450X Specs, Horsepower & Performance Review
TL;DR
- The Kawasaki KX450X pairs the KX450 motocrosser’s 449cc engine with off-road gearing, softer Showa suspension, and a sealed chain built for GNCC and cross-country racing.
- On the standard KX450 platform it’s built from, dyno testing has measured 51.9 to 53.5 peak horsepower across the current-generation engine.
- Wet weight sits at 239.8 pounds with a 1.64-gallon tank, seat height of 37.4 inches, and 305mm/307mm front and rear suspension travel.
- 2026 MSRP is $10,700, and the bike is offered in Lime Green only.
- Starting with the 2027 model year, Kawasaki renamed this bike the KX450FX as part of a lineup-wide return to the “F” naming convention.
What Makes the KX450X Different From the Standard KX450
The KX450X is Kawasaki’s cross-country variant of the KX450 motocrosser, built for GNCC-style off-road racing instead of closed motocross tracks. It shares the same aluminum perimeter frame, 449cc engine, and Brembo front brake as the KX450, but almost everything around that core is retuned for trail and woods riding.
The biggest changes are a shorter final-drive gearing setup, softer Showa suspension valving, and 21-inch front and 18-inch rear wheels wrapped in Dunlop Geomax AT81 tires developed specifically for GNCC racing. Kawasaki also adds a side stand, a sealed chain, and a spark arrester-ready exhaust outlet, none of which the motocross-focused KX450 needs on a track.
Kawasaki KX450X Specs
| Spec | Value |
|---|---|
| Engine | 449cc liquid-cooled DOHC single-cylinder, four-stroke |
| Fuel system | DFI, 44mm Keihin throttle body |
| Transmission | 5-speed, wet multi-disc hydraulic clutch |
| Front suspension | 49mm Showa inverted fork, 305mm travel |
| Rear suspension | Uni-Trak shock w/ piggyback reservoir, 307mm travel |
| Front/rear brake | 270mm / 240mm petal discs, Brembo front caliper |
| Seat height | 37.4 in (950mm) |
| Wet weight | 239.8 lb (109 kg) |
| Fuel capacity | 1.64 gal (6.2 L) |
| Wheels | 21-in front, 18-in rear |
Source: autoevolution, 2025
How Much Horsepower Does the KX450X Make?
Kawasaki doesn’t publish an independent dyno figure for the KX450X, and no major outlet has run one separately from the standard KX450. Because the X shares the same 449cc engine as the motocross KX450, remapped for softer off-road delivery, the KX450’s dyno numbers are the closest verified reference point.
Dirt Rider’s in-house Dynojet 250i dyno has logged the current-generation KX450 engine at 51.9 hp in 2023, 53.1 to 53.5 hp across 2024 through 2026, and roughly 32.6 to 33.1 lb-ft of peak torque over that same span (Dirt Rider, 2025). The KX450X uses this same engine platform, so real-world output on the X should land close to those figures, though its softer ECU mapping and taller gearing change how that power feels on the trail rather than how much of it there is.
Dirt Bike Test’s 2025 review of the KX450X described the power delivery as smooth from bottom to top, with torque low down but a delivery that builds progressively into the mid-range rather than hitting hard off idle (Dirt Bike Test, 2025). That’s a deliberate off-road tune. A motocross bike that hits hard at the crack of the throttle is a liability in tight singletrack where traction comes and goes with every root and rock.
Suspension, Gearing, and Chassis for Off-Road Use
The KX450X keeps the same 49mm Showa coil-spring fork and Uni-Trak rear shock as the motocross KX450, just with softer compression and rebound settings dialed in for trail terrain instead of jump landings. Travel numbers are unchanged: 305mm up front, 307mm out back.
Where the X really separates from the standard bike is gearing. Kawasaki adds a tooth to the rear sprocket on the X, shortening the ratio to help riders manage the 450’s torque at low speed in technical terrain, where a taller motocross gearing setup would feel abrupt (Ultimate MotoCycling, 2022). The tradeoff shows up at the top of the speed range. Testers have noted the five-speed gearbox runs out of ratio in wide-open desert sections, where a six-speed transmission would let the engine settle in rather than bounce off the rev limiter in top gear.
The 21-inch front and 18-inch rear wheel combination, rather than the motocross bike’s 19-inch rear, is standard practice for cross-country racing. The taller front wheel rolls over roots and rocks with less deflection, and the 18-inch rear accepts a wider range of off-road-specific tires than a 19-inch motocross wheel.
What the KX450X Costs and What You Get for It
credit: https://dirtbiketest.com/
The 2026 Kawasaki KX450X carries an MSRP of $10,700 and ships in Lime Green as the only color option (autoevolution, 2025). That price sits close to the standard KX450 motocrosser, which reflects how much hardware carries over between the two bikes rather than the X being a stripped-down or budget variant.
For that price, the KX450X includes Kawasaki Traction Control with weak and strong settings, two power modes, launch control, and Bluetooth connectivity through the Rideology app for on-the-fly engine mapping changes. Those electronics packages used to be reserved for factory race teams a decade ago, and now they come standard on a bike a privateer can buy off a dealer floor.
A Note on the KX450X Name Change
Starting with the 2027 model year, Kawasaki dropped the “X” designation and renamed this bike the KX450FX, restoring the “F” suffix across its entire four-stroke off-road lineup, including the KX450F motocrosser and KX250F/KX250FX. The 2027 KX450FX gets a larger 1.98-gallon fuel tank, a standard skid plate, and standard hand guards on top of the naming change.
If you’re shopping used, listings from 2022 through 2026 will show up under the KX450X name. Anything built from the 2027 model year forward will be listed as a KX450FX, even though it fills the same role in Kawasaki’s lineup.
Frequently Asked Questions
What is the difference between the KX450 and the KX450X?
The KX450 is Kawasaki’s motocross bike, tuned for closed-course tracks with 19-inch rear wheels and firmer suspension. The KX450X uses the same engine and frame but adds softer suspension, shorter gearing, an 18-inch rear wheel, and GNCC-spec Dunlop tires for cross-country and off-road racing.
How much horsepower does the Kawasaki KX450X have?
Kawasaki hasn’t published an independent horsepower figure for the KX450X. Since it shares its engine with the standard KX450, dyno testing of that platform (51.9 to 53.5 hp across recent model years) is the closest verified reference.
Is the KX450X good for beginners?
The KX450X’s smooth, progressive power delivery is more forgiving than a full-on motocross bike’s hit, and testers have described it as friendly for a range of skill levels. That said, it’s still a 240-pound, 450cc race bike, and most beginners are better served starting on a smaller-displacement off-road model.
What replaced the Kawasaki KX450X?
Starting in the 2027 model year, Kawasaki renamed the KX450X to the KX450FX as part of a lineup-wide naming update that brought the “F” suffix back to its four-stroke off-road models.
Does the KX450X have a six-speed transmission?
No. The KX450X uses the same five-speed gearbox as the KX450 motocrosser. Testers have noted the five-speed can run out of ratio in wide-open, high-speed terrain like desert racing, where a six-speed would let the engine settle at a lower rpm.
