We spent several days riding the KFX450R, taking the time to dial it in to our liking. The KFX is a sharp-handling machine with a reputation for being a handful in rough sections coming down from speed. With so much suspension adjustment available we wanted to see how well we could make the machine handle. After our initial rides we found the stock tires bounce too much making it difficult to judge suspension settings, so we installed a set of Kenda Kutter XC tires. The 20-inch rears and 21-inch fronts are the same size as the stock tires, requiring no change in gearing, but bounce significantly less than the stock tires and enhance traction in all conditions.
Since our test rider weighed in at 190 pounds, we stiffened up the suspension by increasing the spring preload from ½ inch to 5⁄8 inch, set compression damping to 11 clicks out and rebound at 19 clicks out. The reason for the significant rebound adjustment was to help the front shocks respond faster in braking bumps. After increasing the rear shock preload for better bottoming resistance we backed high-speed compression all the way out, looking for increased plushness on small bumps. Low-speed compression was left stock, which was also backed all the way out, and rebound damping was set 11 clicks out. Finally, we set up the front wheels parallel with zero toe-in to help slow steering a bit.
We rode the KFX at Horseshoe Bend MX Park in Owenton, Kentucky, (www.horseshoebendmx.com
) and at a private woods track farther north. The tracks at Horseshoe Bend are extremely fun and similar to what you would find at an outdoor national, and our wooded track offered plenty of big jumps as well, but in a more GNCC kind of environment.
Upon throwing a leg over the KFX our riders noticed it greets you with a compact cockpit which puts the controls well within hand, and since some of our test riders were as tall as six feet, we opted to flip the handlebar clamps around to open it up some. High-quality levers with an adjustable-reach brake lever also helped us get comfy on the Kawi, as did the seat, which is low, flat and easy to move around on. Unfortunately, the foam is a bit unforgiving for long trail rides.
As we took the sporty green machine out on the trails, we instantly noticed the KFX450R has an engine that trail enthusiasts will love. It pulls hard and runs smoothly in the first third of the throttle where many 450s feel chugging and jittery. Having usable low-end power really helps in technical, slippery sections, when you’re wearing out at the end of a race or just don’t want to ride hard. As we pushed the light thumb throttle further we could feel the engine’s power increase seamlessly into a strong midrange rush. This made the Kawasaki a blast to rocket out of corners or up steep climbs. The test riders quickly learned the fastest way to ride this engine was by short-shifting. Ride it a gear high and let its strong torque muscle you along. On top the KFX falls off a bit, trading in a larger peak horsepower number for improved ridability. The engine’s desire to be shifted earlier also improves durability since you aren’t always hammering the rev-limiter.
Despite its trail-friendly width, the KFX is almost stable enough for motocross racing. The machine is more than willing to turn and responds immediately to input from the handlebar. This gives you an edge when you want to steal the inside line from your competitors and makes it feel exciting to ride. While it can be a real handful in high-speed braking bumps, dialed in the KFX is pretty predictable though still just a bit nervous. Launching off of jumps the Kawi is quite comfortable as its low center of gravity and centralized mass make it feel light and very maneuverable in the air for stunting or in-flight corrections.