Kawasaki recently unveiled its all-new flagship motocross bike, the KX450. The first change Green made was to the naming convention; it dropped the “F” in the name, seeing as the only full-size dirt bikes it produces are four-strokes. The main changes made to the new-from-the-ground-up motocrosser include a redesigned electric start-equipped engine, a hydraulic clutch, a Showa 49mm coil-spring fork, a new aluminum perimeter frame, and updated bodywork. Kawasaki invited us to Pala Raceway in Southern California to get a first ride impression of the all-new machine, and here’s our thoughts on it after a day of testing.

2019 Kawasaki KX450
Kawasaki recently unveiled its all-new flagship motocross bike, the KX450. The first change was to the naming convention; the “F” in the name was dropped seeing as the only full-size dirt bikes it produces are four-strokes.Jeff Allen

Engine

The new engine comes with electric start, which works great, firing the bike to life immediately. On the track, the 2019 engine retains the previous generation’s already-good power delivery type and improved upon it with noticeably more power in each part of the rpm range. The KX450 has a stronger low-end hit that makes it easy to clear obstacles immediately after exiting a corner. This also allows it to run a gear high in tighter corners and makes it easier to lug the engine on any part of the track. Midrange power is improved as well, with just enough to offer some excitement, but not too much to wear you out or feel uncontrollable. Top-end power is noticeably better and allows you to carry a gear longer than the previous engine. It also revs more freely.

2019 Kawasaki KX450
The main changes made to the new-from-the-ground-up motocrosser include a redesigned electric start-equipped engine, a hydraulic clutch, a Showa 49mm coil-spring fork, a new aluminum perimeter frame, and updated bodywork.Jeff Allen

Kawasaki is the first Japanese manufacturer to spec its flagship motocross bike with a hydraulic clutch. The feel at the lever is excellent and it is very easy to pull in. We noticed at times it can feel almost too easy to pull in, as one of our test riders had to occasionally remove their finger from the clutch to avoid accidentally slipping it.

2019 Kawasaki KX450 Engine
A closer look at the clutch slave cylinder and electric starter.Jeff Allen

The transmission shifts smoothly and each gear is well-spaced. Second gear works well in the tighter corners, and we found we had to cover the shifter and be ready to grab a gear when exiting corners because of how quickly the bike reaches the higher rpm. With the new engine having lots more torque, third gear can be used in some fairly tight corners the previous engine would have struggled with, and the new hydraulic clutch made it easy to modulate the power delivery in these scenarios as well.

2019 Kawasaki KX450 Clutch
The clutch lever has a different shape and is much thinner than the previous model.Jeff Allen

Suspension

The new Showa 49mm coil-spring fork is a major improvement over the previous Showa Triple Air Chamber (TAC) fork that graced the model from 2015 to 2018. The TAC fork had a harsh feeling lower in the stroke that transferred feedback into your hands and arms, but that is all a thing of the past. The new Showa spring fork is much plusher and offers much more comfort in braking bumps as well as big jump landings.

2019 Kawasaki KX450 electric start engine
With the addition of electric start, the kickstart lever has been removed.Jeff Allen

We found that one clicker change on the compression makes a large difference in the fork’s performance, leading us to believe after one day of testing that it has lots of adjustability, but we will confirm this with further testing. Another benefit to the spring fork is it doesn’t have three air pressures to check before riding, one less time-consuming task for when you arrive at the track.

The new Showa shock has a plush feeling overall and the only adjustment we made was stiffening the high-speed compression by a quarter turn. Aside from that, we opted to set the sag a little higher, around 100mm, to give the bike more of a balanced setup.

2019 Kawasaki KX450 corner
The all-new engine retains the previous generation’s already-good power delivery type and improved upon it with noticeably more power in each part of the rpm range.Jeff Allen

Chassis/Handling

Kawasakis are known for having some of the most comfortable ergonomics of any motocross bike, and the same can be said about the all-new KX450. The location of the Renthal 7/8 handlebar, footpegs, and seating position combined with the overall slimness of the plastics makes it very easy to hop on and get acclimated to right away. The KX450 maintains the good straight-line stability of the previous edition, and it also corners better than before due to its easier corner initiation and lighter-weight feeling.

Showa 49mm coil-spring fork
The new Showa 49mm coil-spring fork is a major improvement over the previous Showa Triple Air Chamber (TAC) fork that graced the previous edition from 2015 to 2018.Jeff Allen

The new braking components work well, and although the new rear rotor size has been increased to 250mm, a difference in braking power was not noticed on our day of testing. However, it could be a benefit to those who drag the rear brake. Also, the levers are very thin, especially in comparison to the previous model and nearly all motocross bikes in general.

2019 Kawasaki KX450
The KX450 maintains the good straight-line stability of the previous model and it also corners better than before due to its easier corner initiation and lighter-weight feeling.Jeff Allen

Conclusion

The all-new 2019 Kawasaki KX450 is a big improvement over the previous model. It has a more powerful engine, plusher suspension, and a nimbler, yet still stable, chassis. Our goals in further testing are to continue experimenting with the suspension setup and chassis balance, and also swap out the optional mapping couplers to get a better idea of how they affect the performance of the engine. All in all, we are very happy with the all-new KX450 and look forward to testing it more in the coming weeks.

TECH SPEC

PRICE $9,299
ENGINE 449cc, liquid-cooled, single-cylinder four-stroke
TRANSMISSION/FINAL DRIVE 5-speed/chain
MEASURED HORSEPOWER N/A
MEASURED TORQUE N/A
FRAME Aluminum perimeter
FRONT SUSPENSION Showa 49mm inverted coil-spring telescopic fork adjustable for compression and rebound damping; 12.0-in. travel
REAR SUSPENSION Showa shock adjustable for spring preload, high/low-speed compression damping, and rebound damping; 12.1-in. travel
FRONT BRAKE Nissin single 270mm disc w/ twin-piston caliper
REAR BRAKE Nissin single 250mm disc w/ single piston caliper
WHEELBASE 58.5 in.
SEAT HEIGHT 37.6 in.
FUEL CAPACITY 1.6 gal.
CLAIMED WEIGHT 242 lb. wet
AVAILABLE Now
CONTACT kawasaki.com/