By The Testing Staff of TWMX
Mean New Green
The folks at Kawasaki were dripping with anticipation as they invited the industry press up to the scenic confines of Castillo Ranch for their 2006 KX250F press intro. After sharing their dual-project KXF/RM-Z with Suzuki for the past two years, Kawasaki is more excited than ever with the release of their all-new KX250F. Coined at the intro as their best motocross bike ever produced, the 2006 KXF has all of the tools necessary to make a run for bike of the year in ’06. After all, in only two short years, the championship-winning KX250F has already captured five titles in its original design, and after riding the new ’06, we’re convinced that Kawasaki’s future can only get brighter.
Starting with the visually obvious, the ’06 KX250F sports a brand new all-aluminum perimeter frame that features composite structure, utilizing forged, extruded and cast components. And although the aluminum material may be new to Kawasaki’s motocross bikes, the perimeter frame design has been utilized on KX models dating back to 1990, so there’s no doubting Kawi’s expertise in the area. The slim profile of the frame along with the two-piece radiator shrouds that leave the upper frame spars exposed, make the KX250F feel lighter and narrower beneath the rider than ever before.
Complementing the new frame and adding to the ’06 KX250F’s new and improved handling prowess is a set of Showa twin-chamber front forks. Yep, that’s right… “Showa forks—the first time ever used on a Kawasaki motocross bike.
The rear suspension features a new UNI-TRAK system with revised linkage ratios to suit the new fame and swingarm. And speaking of the new alloy swingarm, it now comes unpainted in ’06, giving it that factory aluminum look to match well with the new frame.
Finishing off the bulk of the chassis improvements are a set of new petal brake discs, which not only help to reduce the overall weight, but also improve the cleaning action for more efficient braking performance. A set of Renthal aluminum handlebars were slapped on to add strength and improved feel, and a new set of short-length grips were added to reduce the vibration transmitted from the bars to the rider. And on top of everything, the styling of the new bodywork on the ’06 KXF looks great—possibly the best-looking Kawi ever!
Although maintaining the same general design, the motor on the new KX250F has received a number of updates, making it much stronger than last year’s bike. Starting with the top-end, the new KXF took on revised intake and exhaust ports, and a revised combustion chamber for improve low- to mid-range performance. The rev-limiter settings and ignition timing have been revised to extend the engine’s over-rev capability, and new cam profiles help increase high-rpm performance without sacrificing low-end grunt. The piston features a thicker crown to compensate for increased power and higher compression ratio. Between the cases, a new crankshaft has been surface-hardened for additional rigidity, and the oil pump has been improved to increase oil flow by nearly 20 percent. Newly designed, high-capacity Denso radiators are now slimmer and feature more tightly packed cores and a new fin design to deliver superior cooling efficiency. And last, but certainly not least, new friction plate material, stiffer clutch springs, and a new clutch lever design to compensate for the higher spring rate have vastly improved the clutch feel at the lever.
So what’s the result of all the changes and updates? Our testers left the Castillo Ranch intro with huge smiles on their faces. The 2006 KX250F is greatly improved over the 2005 model, making it among our absolute favorites to ride. The engine now gives the KX250F a harder-hitting powerband, especially from mid- to high-rpm, and it extends smoothly well into a new and improved overrev. And thanks to the new chassis, including the frame, the swinngarm, new linkage, all the way down to the axle, traction and tracking are as good as it gets, allowing the new motor updates to benefit the overall performance that much more. Shifting the new KXF is smooth and easier than ever before, and the feel at the lever is friendly and plush.
The new frame and suspension setup is awesome, as the ’06 KXF handles amazingly! Designed so that the center of gravity and key chassis dimensions would work together to enhance the rear tire’s ability to drive the KX250F forward, the overall feel of the bike is much more performance-oriented, all the while friendly and easy to ride. The new Showa suspension works as good as it can possibly get in stock form, and even accommodated our heavier testers. Cornering on the KXF is a blast thanks to its stable characteristics and hard-hitting bottom-end power.
All in all we are extremely impressed with Kawasaki’s new 250cc four-stroke, and there’s not a single doubt in our minds that it will be a contender come shootout time. So stay tuned for more, as the magazine test and shootout are still to come…