2011 Kawasaki KX250F Review
One could argue that the development of motocross bikes in the ’00s proceeded at a less-than-rapid pace. Certainly, the bikes showed improvements, but we did not see the developmental leaps that we saw from the riders themselves, who continued to be quite innovative-Bubba Scrub, anyone?
The introduction of electronic fuel injection to MXers seems to have reopened the floodgates of progress, and the new 2011 Kawasaki KX250F shows that this migration of technology has made its way to the Lites class.
Building on the machine that took Christophe Pourcel and Jake Weimer to regional AMA Lites Supercross Championships in ’10, the KX 250 F has inherited the KX450F’s fuel injection, and added a few new twists of its own.
So, let’s get started, literally. Tossing the carburetor-as well developed as they have become-into the dustbin of history is a welcome move for high-performance four-stroke dirt bikes, which can be notoriously difficult to start when warm or after a tumble.
The 2011 Kawasaki KX250F can fire after as few as three rotations of the crankshaft, with electricity to power the EFI system generated from the stroke of the kickstarter. As a result, the motor will light up in one kick, even when it is cold or after being picked up following a toss-away in a corner. This easy-starting capability can prevent a minor mistake from becoming a major setback.
Testing the 2011 KX250F at Budds Creek in Maryland-a traditional stop on the AMA Motocross Championship tour-the power delivery of the updated motor is flawless.
With a 43mm throttle body and an ultra-fine atomizing injector set at a 45-degree angle that sends the fuel/air mix directly into the intake tract, as well as increased compression this year, the 250F pulls extremely hard out of corners. This allowed me to run third through what would normally be a second-gear corner, saving a shift and shaving my lap times.
Even with the strong bottom end it is nearly impossible to bog, the Kawasaki KX250F also is more than willing to rev-no surprise on a demonstrably oversquare motor with a 77mm bore and a stroke less than 54mm.
A four-percent drop in the gearing this year means that the rev limiter is found sooner, but it always kicked in a little later than I expected, giving me just that much more flexibility in gear selection.
Shifting the five-speed transmission is almost effortless thanks to a light-touch clutch and a redesigned mechanism that allows smooth under-power gear changes.
Another major change is the new Separate Function Fork from Showa. In this design, the left tube houses the cartridge damping mechanism, while the right tube contains nothing more than the spring/rod assembly.
Not only does this simplify suspension tuning, but it also reduces weight by over a pound. Kawasaki claims a 25-percent reduction in friction with this design, which is aided by slick high-tech coatings on the legs and tubes.
Building on the new forks, Kawasaki also worked some magic on the perimeter-framed aluminum chassis in an unexpected way, swapping aluminum motor mounts for steel.
According to Kawasaki, factory racers Chad Reed and Ryan Villopoto did blind testing of the different mount materials and both preferred the steel units. I found the ability to fine-tune the suspension, the flex offered by the steel mounts, and a grippier seat, made whoops more manageable. MX races are won and lost in the whoops, so this is an important benefit.
The Showa rear shock is largely unchanged, and once I had the suspension dialed in, the KX250F confidently held its line in corners. Mid-corner adjustments to my line were easily accomplished, as I could move around on the bike at will.
As a six-footer, one might expect me to be cramped on a 250, but the KX250F is roomy and slender, fitting me perfectly. Turn-in has been improved, as the fork-offset has been reduced by a millimeter, yet the bike still has superb straight-line stability.
The predictability of the power, fuel injection, and suspension also combine to make the Kawasaki KX250F an outstanding aerial machine. I felt comfortable hitting long jumps out of corners, as it provides the confidence that the bike will handle any small bump and pulls cleanly when the throttle is quickly pinned.
The Kawasaki tracks perfectly, settles well into the jump, and the 233-pound bike (claimed wet) has a perfectly neutral feel in the air. Fuel injection eliminates any bogging upon landing, and there is no hesitation when returning the throttle to a power-on position.
Off the track, the EFI system can be used in conjunction with an optional ECU Setting Tool that allows the selection of different preset data maps, or fine-tuning a custom map that alters fuel injection and ignition timing.
The tool can also be used as a data logger of a wide range of information-engine rpm, throttle opening, coolant and air temperatures, ignition timing, fuel adjustments, gear position, and system voltage.
Certainly, this motorcycle is more evolutionary than revolutionary, with small changes enhancing the racing experience-for instance, the crankshaft is now balanced to near factory-racer specs, reducing vibration and the fatigue it causes.
However, the rethinking of the front suspension, as well as the flawless application of fuel injection, shows that the minds behind the bikes are still in panic-rev mode, working overtime to eke out any advantage they can over the competition.
The 2011 Kawasaki KX250F is the result of those efforts and, as riders, we are the demanding beneficiaries.
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