The 2006 Kawasaki KX250F whooped some serious tail on a whole lot of Saturdays and Sundays last year. Since it has a couple of Lites-class championships under its belt, courtesy of Grant Langston (Supercross Lites West) and Ryan Villopoto (Motocross Lites), it’s easy to call the bike and Mitch Payton’s Monster Energy/Pro Circuit race team dominant forces.For Kawasaki, this kind of “racing on Sunday” success is priceless. First, it puts bushels of green bikes in the press with results. Second, the company benefits from intense, real-racing R&D. And this, my friends, is what we’re really excited about. Revision years on bikes like the KX250F are usually pretty simple and mostly sweet. But this is definitely not so for this little green monster, except for the sweet part. This year, Kawasaki took its one-year-old to the changing table and went to serious work.Starting with the motor, engineers tweaked and tuned ignition and jetting specs and built a longer and straighter airboot to get the bike to pull off the bottom and accelerate even harder than last year’s model. All of DR’s test riders praised the ’06 for being a traction-hog, always pulling out of the corners with superb grip. Kawasaki apparently found room for improvement. On the top end, the green engineers searched for more, too. A new piston crown and shiny, hand-polished intake ports aim to speed up the air coming in and getting squished. Basically, Team Green went full throttle and attempted to build the ultimate showroom-based racing engine. The company even learned from its few not-so-great racing moments in ’06 and did some work on the motor’s reliability. Valves have become thicker for ’07, and the valve guides are longer to keep as much flex out of the stems as possible. In the bottom end, the crankshaft is now surface-hardened to keep the big-rotating stick as rigid as possible. Transmission components also get a workout with thicker gears, improved shifting components and “beefier dogs” (that’s a direct Kawasaki quote! Mmm mmm… beeeeefy doooogs). Apparently, Kawasaki thinks the new motor is potent enough to deserve this stronger drivetrain.Everyone in motocross understands that power is only half the battle. Without control, the fastest motor is more of a hindrance than a benefit. Last year, most of our testing crew felt the KX250F cornered as well as or better than anything, especially in deep loam or loose dirt. The bike simply carved under most bikes in the deep stuff. But get it on some hardpack and the green bike showed signs of being a little too rigid, leaving something to be desired in the controllability department. For ’07, Kawi addressed this issue directly. By redesigning the frame spars to give more longitudinal flex (that’s like twisting a rubber hose, lengthwise) to the frame, engineers aimed to stick the front and rear through a wider range of corner conditions. Also helping the bike’s turning repertoire is a more compliant front end and some revised fork settings. Out back, a new spring keeps the rear end in line and settled through turns and over bumps.We always ride a few tracks with diverse conditions and put a broad range of riders on board our bikes before we give out our first test. With the KX250F, our methods were no different. The first day after the introduction was on a dry, dusty, hard-packed Racetown 395 circuit. These are not usually the conditions we like to test in (nor the usual conditions at Racetown), but a broken water truck helped us get the blue-groove testing done early. What we discovered right away was that Kawasaki’s claimed engine improvements were more than pillow talk, they were the real deal. The new KX-F motor is still a ripper. But this year it has a more-than-decent increase in high-bottom to mid-top power. Acceleration is impressive, and if you have the traction, the bike will pull your fingers out of their sockets. However, on the hard stuff, it seems Kawasaki compromised some rear-wheel control for boosted ponies. Simply put, the rear end breaks loose easier on the ’07 whereas it was almost always grabbing traction on the ’06. On the bright side, the KX-F seems more than happy grabbing inside lines. We’re confident hard-terrain handling has been improved, as long as you use (not abuse) your throttle hand.The very next morning the bike was taken to the loamy and fast Competitive Edge MX Park. Jumping in the first practice session here is sort of risky as you might find mud and 250F-swallowing deep spots. But the KX-F handled all of the early-morning moisture perfectly. Again for ’07, the KX-F loves the deep stuff. The loam’s traction definitely keeps wheelspin in check. In the deep, follow this mantra: Slam the carb slide open and fear not the dreaded power-slide, but do sit high, as the front end points skyward in a hurry. Cornering accuracy and line choice are simple on this bike, too. Basically, if you can pick up dirt on the track by the handful, riding this bike is almost brainless. Slaying berms two days later at Cahuilla Creek MX Park was another mind-numbing event.Suspension performance at all track days has proven versatile. Jump landings and G-out performance is similar to last year with a little improvement over bottoming. Big and small riders found comfortable settings immediately and felt little or no need to mess with the clickers after adjusting race sag for their weights. We’re currently dialing it in even more and will have setup charts for different weights and abilities when our shootouts hit the pages of Dirt Rider. Until then, keep looking for this green bike to win some early-season races, and if last year’s on-track domination is any indication, Kawasaki will be selling even more of these babies come Monday.Opinions
Since the KX250F was all-new last year, I didn’t expect many changes for ’07. However, after riding the ’06 and ’07 KX250Fs back to back, I came away very impressed with the new machine. Like last year but better, the ’07 absolutely hauls. From way down low all the way to the top, the motor keeps pulling. Whether you like to short-shift it or rev it out, the motor just pulls hard. The Showa suspension works great on both ends, and the new bike did seem a little more planted. Kawasaki took an already awesome bike and fine-tuned it to make it even better. Since my ’06 KX-F still feels solid, the improvements are subtle enough that I am going to stay with it for now.
-Jesse Berg/5’9″/135 lb/NoviceThe leading green machine of ’06 was definitely the KX250F. After all, it won its fair share of Lites titles this season, and no wonder-this thing rips. That’s why Kawi didn’t feel the need to make any drastic changes to the 250F for ’07. For instance, the motor still has that same strong snap off the bottom and the never-ending top-end that was on last year’s machine. The ’07 motor had a minor increase in the midrange power but felt very similar to the previous model. The new KX-F also maintains a low, comfortable feel that screams stability. With this overall comfort, I felt no hesitation making last-minute line changes or even getting into some of the rougher lines. The bike corners excellently in flat-track turns, hard ruts or soft berms. The biggest difference I noticed over the ’06 was a bit of wheelspin due to the increased power out of the midrange. When I wasn’t paying attention to throttle control (or just whacking it wide open), the bike would spin up and break loose easier than last year’s. The KX-F still hooks up and accelerates when traction is plentiful, but not as automatically as before.
-Ryan Orr/5’10″/170 lb/ProLike last year’s model, the ’07 KX250F quickly impressed me with awesome ergonomics and responsive handling. For whatever reason, the frame, handlebar and footpeg position on this bike intersect in a way that fits me like a glove. Even riding through the pits is comfortable, which leads to a confident and stable feeling on the track. The aluminum frame feels narrow and nimble, which is complemented by a smooth seat-to-tank transition that encourages the pilot to take a good, aggressive riding position. The bike turns when you tell it to, pounds through the roughest sections of the track with ease and doesn’t fuss about cutting inside lines or slippery off-cambers. The 250F’s motor delivers a strong, meaty hit that provides a usable amount of power up into the higher rpm, and I never felt the transmission skip a beat. The engine’s ability to crank out ponies does have a few small drawbacks, as low-traction situations proved to be tricky with the KX-F’s hard-hitting ways, resulting in an undesirable left-and-right slide of the spinning back end. All in all, though, the Kawasaki remains an impressive stock machine with an overall package that performs just how I think a 250F should.
-Chris Denison/5’10″/155 lb/IntermediateSpecifications
Claimed dry weight: 204 lb
Actual weight (ready to ride, no fuel): 222 lb
Seat height: 37.75 in.
Seat-to-footpeg distance: 21.0 in.