2021 Kawasaki KX450X Review: Off-Road Motorcycle Test (14 Fast Facts)

October 18, 2020

Kawasaki is re-entering the open-class off-road racing market in 2021 with its all-new KX450X motorcycles. The 2021 Kawasaki KX450X is 100 percent built for racing and not meant to be a trail bike or used for a Sunday cruise. We’ve already had a detailed first look at the KX450X, so check that out for all the technical details. We’re about to go riding.

Our first ride on the 2021 Kawasaki KX450X was at the top-shelf Cahuilla Creek Motocross facility in the San Jacinto Mountains of Southern California. We didn’t spend much time on the MX track, though. Instead, we concentrated on a five-mile off-road loop that included a rock section, flowing single-track, and tight single-track. The course was also summer-dry and had heavily whooped out sections. It was a good test for any off-road race bike.

The formula Kawasaki used to create KX450X is a familiar one. Kawasaki started with its popular and much-praised KX450 motocross bike. An 18-inch rear wheel was installed, along with a kickstand, one-tooth larger rear sprocket, softer off-road suspension, and protection for the motor and rear disc. The rest of the 450X is pure KX.

The 2021 Kawasaki 450X has excellent chassis, just like the KX450 we recently tested. Having spent time on the motocross version, I already knew the 450X would be a great handling bike. However, I was anxious to feel how they handled out on the trail. The 450X turns nice and easy, especially in the tight and rough single track where you’re in the standing position. At speed in the whooped-out sections, the KX450X stays nice and straight with no harsh feeling transmitted through the frame.

The 2021 KX450X’s Showa suspension has softer spring rates than the KX450 MXer, with valving to match. Before I took both bikes out, the sag was set at 105mm. Out on the off-road loop, the 450X felt a little harsh through the lower speed sections. I came in and talked to the Showa tech; he went two clickers softer on the compression, both front and rear. I didn’t think it would be a major change. However, he explained that the Showa A-Kit forks aren’t all that different internally, but use 1/4 clicks. As a result, two full clicks is not a minor change.

Setting up the suspension correctly makes a huge difference. With the reduced compression damping, the KX450X felt much better. Bump absorption was much improved, and the motorcycle felt a lot more planted. That gives me more confidence to ride at my ability. The side-effect was in the faster sections. When hitting small jumps or bigger whoops, the suspension was rebounding too quick and bouncing back at me. The tech went one click in (stiffer) on the rebound, front and rear, to fix that. With this change, the suspension felt great at all speeds—no other mods were needed.

The 2021 Kawasaki KX450X has a very fast motor with a nice broad powerband. Its linear power delivery works nicely in an off-road environment. The slightly lower gearing of the 450X kept me in the meat of the powerband and kept from stalling the bike in most technical sections. Just like the MX version, the X comes with three couplers with different engine mapping. Surprisingly to me, I preferred the most aggressive map/coupler. I thought it would feel too aggressive, but it didn’t, as the overall nature of the motor is smooth. I prefer the aggressive map because it provides a little more torque and bottom end power. That really helps when riding at low rpm through the tight terrain.

The KX450X’s gearing is perfect for an off-road bike. I spent most of my time in 3rd gear, which keeps the engine in the meat of the powerband or just a little lower in the tight sections. When the loop opened up, I was able to run it through the gears. Top speed was never an issue.

The new hydraulic clutch works great. I abused the clutch while riding on the tight and technical sections, but it felt great no matter how hard I was on it. The clutch has a fantastic clutch feel and pull.

18-inch rear wheels are mandatory for off-road bikes. It was an easy thing for Kawasaki to add, and it’s what off-road guys want. The Dunlop Geomax AT81 tires are built for off-road. We have tried them on other off-road motorcycles in the past and didn’t really like them. The Dunlop’s performance at Cahuilla on the Kawasaki KX450X didn’t change our opinions.

We like the lower peg positioning even more out on the trail. It was the same when we tested the KX450 motocrosser, but it makes even more of a difference off-road because you’re up on the pegs so much more. Putting the pegs in the bottom position lowers your center of gravity when standing, helps with traction, and aids in balancing the motorcycle.

Electric starting and kickstands are essential additions. Kawasaki has been a bit late to the e-start game, and it is even more critical on an off-road motorcycle than a motocrosser. When I first saw the kickstand on the KX450X, it looked like it stuck out quite a bit and would be in the way. Once underway, I never even noticed it. I was never aware of the kickstand with my boot, or when bouncing through the whoops and over jumps.

The small details add up. A Renthal Fatbar, adjustable bar mounts, adjustable peg mounts, superb ergonomics, and a comfortable seat with an effective gripper cover, all add up to a top-quality motorcycle. The dislikes are small—the levers are too thin and grips on the hard side.

The 2021 Kawasaki KX450X is not a trail bike, or even an Enduro bike. As such, Kawasaki didn’t add lights or mellow the power with heavy flywheels or soft mapping. Although softened from MX, the suspension is still very firm for trail riding. The muffler lacks a spark arrestor, and it is a competition-only Red Sticker motorcycle here in California. As an off-road racer, I would like to see a larger fuel tank, handguards, and a six-speed transmission.

I’m a big fan of the 2021 Kawasaki KX450X, mainly due to the excellent handling characteristics and overall feel. With the KX450 and KX450X sharing almost all the parts, there’s plenty of aftermarket goodies available to make the X the off-road racing motorcycle you desire.

Photography by Drew Ruiz

RIDING STYLE

Helmet: Shoei VFX-Evo
Goggles: EKS Brand EKS-S
Jersey, pants, and gloves: Alpinestars Racer Tech
Boots: Alpinestars Tech 10

2021 Kawasaki KX450X Specs

ENGINE

Type: Single-cylinder four-stroke
Displacement: 449cc
Bore x stroke: 96.0 x 62.1mm
Compression ratio: 12.5:1
Starting: Electric
Fueling: EFI w/ 44mm Keihin throttle body w/ dual injectors
Transmission: 5-speed
Clutch: Hydraulically actuated w/ coned-disc spring
Final drive: Chain

CHASSIS

Frame: Aluminum perimeter
Handlebar: Renthal Fatbar
Front suspension; travel: Compression- and rebound-damping adjustable Showa 49mm inverted fork; 12.0 inches
Rear suspension; travel: Linkage-assisted fully adjustable Showa piggyback reservoir shock; 12.1 inches
Tires: Dunlop Geomax AT81
Front tire: 80/100 x 21
Rear tire: 120/90 x 18
Front brake: Semi-floating 270mm Braking petal disc w/ dual-piston Nissin caliper
Rear brake: Single 240mm Braking petal disc w/ single-piston Nissin caliper

DIMENSIONS and CAPACITIES