In 2009, the Kawasaki KX450F was a close runner-up for Best Motocrosser in Cycle World’s Ten Best Bikes that year (even if it was a 2010 model that qualified for voting because of its early release). At the time, the big KX impressed us with its excellent top-end power, great fuel injection and well-balanced chassis. Although minimal changes were made for 2011, the well-chosen tweaks improved this already impressive motocross machine. Our first taste of the 2011 KX450F occurred in SoCal’s high desert at Racetown 395 in Adelanto. A perfectly prepped track greeted us in the morning, with deep loamy berms, while later in the day it got much rougher and gave the suspension a good test.
With hot-shoe Off-Road Editor Ryan Dudek out of the country on a European press launch, the testing fell to Vet-level staff guys Mark Cernicky, Jeff Allen (photog) and me. What we discovered is that the KX450F is a very usable bike that suits a large cross-section of riders. A big part of this flexibility is thanks to the engine. Linear power delivery makes it very easy to control the bike. With the ECU set right in the middle (standard) of seven selectable presets, there isn’t a big hit anywhere, just progressive power. On a couple of long, loamy sand whoop sections, all the rider had to do was rev the bike and top-end power yanked it through easily. On the other end of the rpm scale, when trying to finesse the throttle exiting slick corners, the power could be laid down smoothly, to help you keep the back end from snapping sideways.
Changes made to the 449cc, DOHC, four-valve engine, include new ECU mapping to improve low-end response by providing a hotter and longer-duration spark. Further, piston shape was modified in response to alterations made to the higher-volume, quieter, stainless-steel exhaust system. For those looking to further refine ECU tuning, the Kawasaki Setting Tool allows owners to adjust fuel and ignition for different tracks, conditions or personal preferences. It can also be used as a data logger, recording up to six hours of info. The ECU is accessed via a laptop rather than the dedicated handheld unit as sold by Yamaha for its YZ450F.
Having recently spent time aboard the Honda CRF450R and Yamaha YZ450F, we were impressed with how easily the KX could be kicked to life with its batteryless fuel-injection system; even when the bike was very hot it would restart on the first kick more often than not.
The KX450F’s suspension settings have been revised for both the 48mm Kayaba Air-Oil-Separate fork and Kayaba shock. Handling was sharp and quick-turning without being twitchy, and although the track never got super rough, the big KX felt very stable through braking bumps and ruts that developed during the afternoon. At our Vet-paced speed, the suspension felt plush, yet sucked up big jump landings without harsh bottoming. Braking performance was quite good, with nice power and progressive action from the front and also from the not-too-sensitive rear unit.
As far as ergonomics and rider interface go, the KX is super comfortable. The seat is one of the softer thrones that we can think of; gripper material was added to the sides to help keep you in place. The bend of the Renthal handlebar results in a comfortable cockpit, and we like that the stock piece is of high quality, making it one less item that needs to be changed after purchase. The price of the ’11 model is $8149 (up $100 over last year), which isn’t cheap, but what you get in return is a great all-around bike that can be easily fine-tuned to your preferences.
|Engine type||dohc Single|
|Bore x stroke||96.0 x 62.1mm|
|Front wheel travel||12.4 in.|
|Rear wheel travel||12.4 in.|
|Fuel capacity||1.9 gal.|
|Seat height||37.8 in.|
|Claimed wet weight||250 lb.|