MXA TECH SPEC: 10 THINGS YOU NEED TO KNOW ABOUT THE 2020 KAWASAKI KX450
(1) Forks. Every MXA test rider loved the feel of the 2020 Kawasaki KX450 Showa forks. They were plush, comfortable and, best of all, followed the ground better than the previous TAC air forks. The slower the test rider, the better the forks, but as the test rider’s speed increased, the forks quickly became too soft. Our quick fix was to keep the stock 5.0 N/m spring in one leg and put the optional 5.2 N/m spring in the other leg. National-speed Pros will need the 5.2 springs in both legs.
(2) Clutch. Although the 2020 KX450 clutch is hydraulically activated, the clutch itself isn’t very good. We recommend removing the miniaturized fiber plate, ring-like judder spring and flat spacer, and replacing them with one additional full-size clutch plate. Additionally, we run three stiffer Pro Circuit clutch springs. The leverage ratio of the stock clutch lever does not generate enough hydraulic piston movement to release the clutch fully. When your clutch lever hits the two fingers that are still on the grip, the clutch is actually slipping. Even though you think you’ve pulled the clutch in, you haven’t. We went to the guy who builds Eli Tomac’s clutch lever, and he told us to run an ARC Flip-Chip-equipped PowerLever. It allows you to change the leverage ratio and make the clutch disengage at six different points on the lever pull.
(3) Rear brake. The jumbo-sized 250mm rear rotor is too touchy. To lessen the grabbiness, we chamfered the edges of the rear brake pads at an angle to allow the pads to slide onto the rotor more efficiently and to downsize the pads’ surface area. We also removed the black plastic rotor guard from under the swingarm, because it blocks airflow to the rotor (Honda removed its guard in 2020).
(4) Rear brake pedal. The rear brake pedal can be adjusted upward but not downward. To cure this, we hacksawed three threads off the bottom of the threaded master cylinder rod to give the pedal more downward free play; that way, a boot can touch it without locking up the brakes by accident.
(5) Maps. The stock green coupler offers the best ECU map. It is significantly stronger than the mellower black coupler and a lot less hyperkinetic than the aggressive white coupler. If you compare the black map to the green map, the black map gives up 1 to 2 horsepower. As for the aggressive white coupler, it does not produce more horsepower than the stock coupler, just a crisper feel.
(6) Grips. Kawasaki’s black grips look like the real thing, but don’t fall for it. It is a trick. Any aftermarket grip is twice as comfortable as the stock KX grips.
(7) Plastics. Kawasakis have very brittle plastic. Roost cracks the fork guards. The front number plate cracks down the center, and the elongated arms of the radiator wings crack vertically. Order aftermarket plastic. It is much more durable.
(8) Airbox. To get to the air filter, you need both an 8mm and a 10mm T-handle. That is one wrench too many. Additionally, the nut plate behind the top bolt falls out of the fender when you loosen the bolt. Finally, the airbox is very small and the design is very weird.
(9) Chain roller. The lower chain roller—the one under the frame that keeps the chain from whipping as it spins off the countershaft sprocket—self-destructs in an amazingly short amount of time. Considering the chain roller issue and Kawasaki’s long-term problems with its rear chain guide, you should order TM Designworks parts on day one.
(10) Overheating. We run a 2.0 kg/cm2 Twin Air Ice Flow radiator cap to keep the radiator from spewing fluid.