Kawasaki has made quite an entry with the all-new KX250F two years ago, but with the stiff competition encountered on the motocross track, a radical new approach had to be made towards this bike. The recipe is the same as in the case of its bigger sibling, the KX450F: a lightened engine that pulls stronger finds its place on the refined chassis. The look is also refreshed so Kawasaki’s out with the best against its competitors.
Purely designed for racing, the 2009 banger comes with a host of refinements that end up making it pull stronger, smoother and linear. First, Kawasaki modified the intake ports in the cylinder head in order for these to host properly the new titanium valves. This change and new addition have a great result on the engine’s performance and power delivery, making it rev freer, stronger and yet smoother. But what goes in must come out, and the burned fuel is being taken through a tapered titanium exhaust pipe, also aiming at a greater power delivery and smoothening out the hit when the throttle is opened.
Such an important engine revision couldn’t have passed without reestablishing the crankshaft’s balance factor. As a result of that, the engine will vibrate significantly lesser and still get a stronger bang in the low-and-mid rpm range.
Making an engine pull stronger will always determine a check or two on its cooling system in order to make sure that it stays up for the challenge. But in this case there was the need for a new water jacket routing which increases flow. Dealing with that are the larger radiators with new, four-blade louvers for greater cooling effectiveness.
In order to reduce weight and mechanical loss, the engine oil volume got significantly lower (1.3L) and the KX450F made sure to provide a crankcase scavenge pump oil filter to its smaller sibling.
The new model also comes with a longer tranny life expectation as there are bigger intervals between the gear shafts now, allowing stronger gears, clutch and generator covers. Clutch cable holder is now integrated into the crankcase, improving clutch feel and a new ratchet drive shift system was implemented. The lever ratios, spring rates and shaft locations were also revised.
In order to keep the bike steady under hard acceleration with less effort, Kawasaki adds a new frame and sub-frame to the already light and impressive package. Well, it is now even lighter (with 2.2 lbs, to be precise) and it is all due to the forged, extruded cast parts. Reshaping the frame spars narrowed the overall profile with 6mm, leaving the rider more in control as it keeps its knees tighter on the machine’s body.
Just like on the KX450F, the “D” profile swingarm now pivots from a higher position, improving traction and control feel. Also, the Uni-Trak rear suspension system is being positioned below the swingarm, offering longer rear stroke and more precise rear suspension tuning.
A 50mm piston diameter Showa shock comes new on the KX and has revised layout and damping characteristics. Shock internals feature Kashima Coat.
Up front there are the new Showa fork upgrades with titanium coated inner tubes. Surface inside the outer fork tubes is Kashima Coated for friction reduction. Front suspension new settings offer even more control through tight corners.
Kawasaki and Suzuki started their collaboration back in 2002 and a first result of this strategic alliance was the KX250F. Introduced as a 250cc liquid-cooled DOHC four-stroke, four-valve motocross bike, it immediately started to prove its point on the track. But problems to the cooling and ignition systems made more than a few riders doubt its capabilities until 2005 when the two makers would have again team up and finish what they’ve started three years earlier.
A year later, Kawasaki started producing the 250cc four-stroke banger on its own and the bike was dreadfully improved. There was the big aluminum perimeter frame change, the almost brand new engine and by that time Showa would have provided the suspensions.
2008 was also quite a big year for this Kawasaki dirt bike as its engine got a redesigned crank and heavier flywheel for better torque and response in the low rpm range. Engine mounts were moved 10mm further from it for better balance. The gearbox had to deal with these changes by offering more consistent gear changes so it did.
This is also the year when the black alumite coated rims were added.
The association between the two motorcycle makers didn’t provided results only for Kawasaki. Suzuki would have also presented its RM-Z250 which, even though initially identical to the KX250F, on the track they were the biggest enemies.
After they’ve dropped the union in 2006, the models started going their own way, but still remained similar in many ways. So the RM-Z250 is also powered by a carbureted 249cc liquid-cooled, DOHC four-stroke engine with similar performance of the one found on the green little beast.
Also new for 2009 and having an MSRP of only $6,299, it offers goodies such as aluminum-alloy frame, aluminum swingarm, Renthal handlebars and Showa suspensions.
With a single twist of the throttle, Yamaha manages to beat both bikes mentioned before as for 2009 it comes with chances to the exhaust system. This offers greater throttle response in the low-and-mid rpm range and together with chassis upgrades it becomes very easy to maneuver on the bumps and jumps. You will say that the Kawasaki and Suzuki also offer these things for pretty much the same money (the Yamaha costs $6,549), but what makes it angrier is the five-titanium-valved engine. This has always been Yamaha’s advantage and it didn’t miss the YZ250F.
Honda still doesn’t launch the 2009 motocross lineup so the CRF250R remains as you know it.
Kawasaki made sure that their new 250cc four-stroke motocross model would look as good as it will go and in order for that to became reality, there was designed a new, sleeker bodywork featuring a one-piece, dual-injected, two-tone black and green plastic shrouds and side number plates. The narrowed urethane foam seat blends perfectly in with the body components and the graphics make it stand out as a strong potential winner.
Even though stylish and very aggressive, this bike was actually designed to accommodate its rider as good as a motocross bike can so that competing wouldn’t become more soliciting than it already is. This is how the 50mm wide footpegs ended up on the bike and although they don’t make it stand out, they have a great influence on the rider’s position when riding, something that does stand out immediately.
Available Lime Green painted, the new KX250X is top notch finished, but if you feel like radically individualizing yourself out on the track, there is the Monster Energy Version. This last comes with a great new Ebony paintwork and graphics.
Competition bikes were never cheap, but always well worth the buck spent on them and the bike reviewed today makes no exception. Offered for an MSRP of $6,499, it proves nor only competitive on the bumps and jumps, but also on the showroom floor.
For the most fastidious of you out there, the Monster Energy Version of the bike comes with an MSRP of only $6,699. Easy to make that decision, I guess.
Following a great evolutionary trajectory, the Kawasaki KX250F ends up being one of the fiercest competitors found on motocross tracks around the world.
Powerful and aggressive, the bike knows how to deal with the engine’s capabilities and it proves it every time a motocross race is ended with the Kawasaki name winning table.
Engine and Transmission
Engine: Four-stroke single with DOHC and four valves
Bore x stroke: 77.0 x 53.6mm
Carburetion: Keihin FCR37 and hot start circuit
Compression ratio: 13.2:1
Ignition: Digital CDI with K-TRIC throttle position sensor
Transmission: Five-speed with wet multi-disc manual clutch
Final drive: Chain
Chassis and Dimensions
Frame: Aluminum perimeter
Rake / trail: 27.7 degrees / 4.8 in.
Front suspension / wheel travel: 47mm inverted Showa twin-chamber telescopic fork with 16-way compression and rebound damping / 12.4 in.
Rear suspension / wheel travel: UNI-TRAK® linkage system and Showa shock with 13-way low-speed and stepless high-speed compression damping, 17-way rebound damping and fully adjustable spring preload / 12.2 in.
Front tire: 80/100-21
Rear tire: 100/90-19
Front brake: Single semi-floating 250mm petal disc with dual piston caliper
Rear brake: Single 240mm petal disc with single-piston caliper
Overall length: 85.4 in.
Overall width: 32.3 in.
Overall height: 50.0 in.
Wheelbase: 57.9 in.
Ground clearance: 13.4 in.
Seat height: 37.6 in.
Curb weight: 229.9 lbs.
Fuel capacity: 2.1 gal.