2021 Kawasaki KX450 Review First Ride
Subtle changes improve an already-great bike.
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 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.
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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
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.
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.
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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 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.
2021 Kawasaki KX450 Overall Impression
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.
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