2021 Kawasaki KX450 Review First Ride

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Riding the 2021 Kawasaki KX450 at Glen Helen Raceway in San Bernardino, California. (Drew Ruiz/)

Kawasaki was the first manufacturer out of the gate to host a 2021 bike test with its KX450. We joined Team Green at Glen Helen Raceway in San Bernardino, California, to shake down its mildly updated flagship motocross bike, which has won Dirt Rider’s 450 Motocross Shootout the past two years.

The new Renthal Fatbar 839-bend handlebar makes it easier to get over the front of the bike, which is especially helpful when cornering. (Drew Ruiz/)

The changes made to the KX450 for MY21 include a new coned disc-spring hydraulic clutch, larger-diameter clutch plates with a revised friction material, a new dry film lubricant coating on the piston skirt, and the switch to a Renthal Fatbar 839-bend handlebar, which is 1-1/8 inches in diameter and the same bar and bend that comes stock on the 2019 and 2020 Honda CRF450R.

Related: 2021 Kawasaki Motocross And Cross-Country Models Released

Compared to the 2019–2020 KX450′s Renthal 7/8-inch-diameter, 971-bend handlebar, the 2021 model’s Renthal Fatbar 839-bend bar is 6mm lower, has 11mm less rise, and 2mm less sweep. The only similarities the two Renthal handlebars share in terms of dimensions are their width at 802mm.

2021 Kawasaki KX450 Engine

The KX450 receives a few engine updates for 2021 in the form of a new coned disc-spring hydraulic clutch, larger-diameter clutch plates with a revised friction material, and a new dry film lubricant coating on the piston skirt. (Drew Ruiz/)

With its crisp throttle response, the KX450 gets up and goes, which is especially noticeable when exiting corners. This combined with its plentiful bottom-end power and nearly effortless clutch pull makes it easy to manipulate the power at low rpm, even when riding a gear high. The engine continues to pull into the high rpm long enough that we didn’t have to upshift to third when climbing most of Glen Helen’s smaller hills. Since Kawasaki granted the KX450 a hydraulic clutch in 2019, we have praised it for its remarkably easy lever pull, and the changes made to it for 2021 give it an ever lighter feel at the lever.

2021 Kawasaki KX450 Suspension

Very few clicker changes, if any, are needed to get most test riders comfortable with the Showa 49mm coil-spring fork and Showa shock. They are fantastic. (Drew Ruiz/)

No changes were made to the KX450′s Showa 49mm coil-spring fork and Showa shock for 2021. The components have remained the same since the KX450 enjoyed a complete overhaul in 2019, which is great because the front and rear suspension work excellently. The Showa components offer a plush yet progressive feel throughout the stroke, which isn’t hampered when making clicker changes in one direction or the other. Both of our test riders—one a former AMA Pro Supercross racer and the other a novice-level motocross rider—made no more than two clicker changes on the fork compression and were able to find a comfortable setting they were happy with.

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With its stock 5.0 Nm fork and 54 Nm shock spring rates, the recommended weight range for the 2021 Kawasaki KX450 is 160 to 180 pounds. We have found this to be a very balanced setup for the majority of test riders. For those who weigh 175 pounds or more and pro-level riders who come in at the higher end of the recommended weight range, we have experimented with adding an optional, one-rate-stiffer spring of 5.2 Nm in one of the fork legs and leaving the other with the stock 5.0 Nm spring, effectively giving the fork a spring rate of 5.1 Nm, which Showa does not offer. This minimizes bottoming under large impacts for heavier riders, but doesn’t take away from the fork’s plush feel. It’s worth noting that we have been able to set the shock sag at the recommended 104mm setting with the stock 54 Nm spring rate for riders up to 190 pounds as well.

2021 Kawasaki KX450 Chassis/Handling

Kawasaki has dropped its prior Renthal 971-bend handlebar in favor of a Renthal Fatbar 839-bend bar, which is 6mm lower, has 11mm less rise, and 2mm less sweep than the outgoing 7/8-inch bar. (Drew Ruiz/)

For the past two years, the KX450 has had the best chassis in its class. While it’s too early to tell whether it will retain that accolade, being that it’s the first MY21 450cc motocross bike we’ve tested this year, we wouldn’t be entirely surprised if it did. The KX450 not only offers neutral handling characteristics, the frame also does an excellent job of working with the suspension to absorb impacts, yet retains a firm enough feel to respond well to rider input. Kawasaki’s current generation flagship motocross bike has a long list of positive qualities, but its chassis may very well be its standout feature.

The KX450’s frame has an excellent rigidity balance. Its compliancy enables it to help the suspension absorb impacts, yet it’s firm enough to allow for precise handling. (Drew Ruiz/)

The KX450′s ergonomics are excellent with a slim profile from front to rear and a flat seat that is easy to move forward and back on. We commend Kawasaki for changing one of the few complaints we had about the 2019–2020 KX450—the handlebar. We felt the prior Renthal 971-bend bar was too high and threw off the bike’s otherwise-good rider triangle. With the new Renthal Fatbar, the rider triangle is noticeably improved as its lower height puts you in more of a neutral position while riding. One of our few minor complaints about the KX450 is that its 250mm rear brake rotor is a little touchy and makes it too easy to lock up the rear brake at times.

One of our few complaints about the current generation KX450 is its 250mm rear brake rotor. It’s a bit touchy and makes it too easy to lock up the rear brake at times. (Drew Ruiz/)

2021 Kawasaki KX450 Overall Impression

The KX450 gets up and goes due to its crisp throttle response. (Drew Ruiz/)

With its crisp throttle response, plush suspension, phenomenal chassis, and agreeable ergonomics, the current-generation KX450 has a lot going for it. Team Green has a well-rounded package for its flagship motocross bike and it heads into the 2021 450 Motocross Shootout with a lot going for it; only time will tell if it can make it a three-peat this year.

The current generation KX450 has a lot going for it. An even easier clutch pull and a better-proportioned rider triangle make it even better in 2021. (Drew Ruiz/)

Gearbox

Helmet: Shoei VFX-EVO

Goggle: 100% Armega

Jersey: Fox Racing 360

Gloves: Fox Racing 360

Pant: Fox Racing 360

Boots: Fox Racing Instinct

2021 Kawasaki KX450 Tech Spec

PRICE	$9,399
ENGINE	449cc, DOHC, liquid-cooled, single-cylinder four-stroke
TRANSMISSION/FINAL DRIVE	5-speed/chain
FRAME	Aluminum perimeter
FRONT SUSPENSION	Showa 49mm coil-spring fork adjustable for compression and rebound damping; 12.0-in. travel
REAR SUSPENSION	Showa shock adjustable for spring preload, high-/low-speed compression, and rebound damping; 12.1-in. travel
FRONT BRAKE	Nissin 2-piston caliper, 270mm disc
REAR BRAKE	Nissin 1-piston caliper, 250mm disc
WHEELBASE	58.5 in.
SEAT HEIGHT	37.6 in.
FUEL CAPACITY	1.6 gal.
CLAIMED WEIGHT	243 lb. wet
AVAILABLE	Now
CONTACT	kawasaki.com

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