Kawasaki now offers the KX250F motocross model as a 2010 model year. Not only that, but the quarter-liter racer is entirely new as a result of engineers aiming towards a higher revving and implicit more powerful, but also more reliable engine. Once you’ve done that, every single piece of the machine qualifies for a proper revision and that’s how dirt bikes end up being tweaked each and every year.
In order to know what needs to be improved on a bike, there’s the need for proper feedback and the fact that Kawasaki competes in the AMA Supercross Championship did help engineers come up with the right answers.
The bike needs to remain one of the sharpest steering dirt bikes in its class and the fine tuning is supposed to make that possible. Also, speed is of the essence as the engine now gets a new piston with a bridged-box bottom, which is a first on production bikes. The piece of
36.48-hp carbureted single-cylinder engine
crucial importance for any engine stands both for performance and reliability. These aspects are also covered by the electrofusion treatment on the cylinder bore, revised oil pump rotors and a wider big-end bearing that this new model year features. The radiators are increased in size in order to cope with the new temperatures involved and also weigh less, just like the entire new engine does.
Kawasaki claims their new KX250F will even vibrate less, while the transmission and clutch have been optimized for the new engine.
While this Kawi’s aluminum perimeter frame doesn’t come as a surprise, the news in the chassis chapter is the even lower center of gravity and front-to-rear weight distribution. This last aspect is achieved due to the racing suspensions and mostly the swingarm. The bike is claimed to be more stable and precise; in other words, faster around the track.
Ergonomics have also been modified for a more natural riding position and the styling is totally new on both bikes. The Kawasaki KX250F Monster Energy is simply a lighter, faster and more aggressive piece of machinery, but still a 2009 model year for now.
Kawasaki now carries on competing with the very same Japanese contenders as well as with the European ones. These first, the Honda CRF50R , Yamaha YZ250F and the Suzuki RM-Z250 are by now also 2010 model years, but so is Huski’s TC250 model. Kawasaki doesn’t fall behind with its 250 SX-F model either although this is still a 2009 model year.
The striking difference between the simple KX250F and the KX250F Monster Energy is achieved with the help of styling. Both models feature similar plastic covers, triple clamps, number plates, and engine covers, meaning that the overall shape is exactly the same in both cases. What differ are the color schemes and graphics.
Also in both cases, the seats are redesigned and offer the same grip that is due to the slip-resistant top surface material. Just look for a Lime Green color scheme if the standard KX250F is your choice and for an Ebony one is the Monster Energy version sounds better to you.
“The motor on this thing is really strong,” said pro-level test rider Matt Armstrong. “I really noticed it on the mid-range. It really kicks as soon as you start revving it and it transitions into a decent top-end. Up top, it revs out really high but it kind of peters out a bit.” – motorcycle-usa
“As for cornering, Parker said the bike worked equally well whether railing a berm or taking the point-and-shoot approach to a corner. The bike responded well to rider input, going where the rider wants it to without a fight.” – motorcycle
“Kawasaki aimed at better handling balance, better front to rear suspension balance and more useable bottom and mid power. To us it feels like they got ’r done.” – dirtrider
“What did Kawasaki do to advance the KX250F? They made plenty of refinements that focused on durability and improved performance. Kawasaki aimed at increasing power and getting the engine to rev quicker, all while making sure that durability was also improved.” – motocrossactionmag
“At first, we were surprised - and maybe a little disappointed, too - that the new Kawasaki was not fuel-injected, but, as it turns out, we’re okay that, since the Kawi carburates so well anyway. Our test bike ran just fine right out of the crate.” – cyclenews
Starting at $6,999, the 2010 Kawasaki KX250F sounds like a great bang for the buck, while a 2009 Kawasaki KX250F Monster Energy starts at $6,699. I did mention that Kawi hasn’t yet released the info on the 2010 Monster Energy. Still, this might just be the bike for those who search for a special thing without the special price.
Getting on the actual bike is of the essence for even the slightest impression so until then we’ll just have to say that it looks like a champion’s bike. It will eventually have to prove it to us too.
Engine and Transmission
- Engine: Four-stroke single with DOHC and four valves
- Displacement: 249cc
- Bore x stroke: 77.0 x 53.6mm
- Cooling: Liquid
- 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: 27.4 degrees / 4.7 in. ; 27.7 degrees / 4.8 in. - Monster Energy version
- 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: 231.4 Lbs. ; 229.9 lbs. - Monster Energy version
- Fuel capacity: 2.1 Gal.
Features & Benefits
All-new Engine higher performing and more durable
- 249cc, liquid-cooled, four-stroke, four-valve, DOHC engine delivers hard-hitting power from mid- to high-rpm
- Engine oil capacity decreased from 1.5L on previous model to 1.3L, reducing overall weight and mechanical losses
New Top End
- New cylinder head has revised intake ports for improved performance at all rpm, especially in the high-rpm range
- Special coating applied to the intake port cores during the casting process gives the intake ports extremely smooth surfaces and increased intake efficiency across the rev range
- Head gasket now silicon coated for improved sealing
- New cam chain tensioner spring reduces mechanical loss by approximately 30 percent
New Intake and Exhaust Valves
- Formed from a new, highly rigid, titanium material, the lightweight 31mm intake and 25mm exhaust valves reduce reciprocating weight and offer greater high-rpm reliability
- Ultra-strong valves have extremely thin valve stems on par with those found in supersport machines with the intake valves featuring 0.25mm thicker heads for increased strength
New Titanium Exhaust Pipe
- Tapered, expanding from approximately 35 to 45mm for better throttle response and performance at all rpm
- New silencer body shape to meet 99dB AMA noise regulations
New Crankshaft Balance
- A revised crank web significantly increases the crankshaft balance efficiency; it’s now on par with the factory racers
- Results in reduced engine vibration, smoother power delivery and increased performance in the mid-high rpm range
- New 6.4mm wider radiators have a 6 percent larger capacity than previous model
- Very slim, high-capacity Denso radiators feature tightly packed cores and a fin design deliver superior cooling efficiency for excellent heat dispersion
- Radiator louvers increased from three to four and decreased in size and angle for less overlap and higher air flow
- Revised cylinder head water jacket routes coolant via the front of the cylinder head for a more even cooling performance
- Ratchet drive shift mechanism replaces the previous models gear driven system for improved shift feel and durability
- Improved feel at the clutch lever by integrating the clutch cable holder with the crankcase
- Increasing the interval between gear shafts 1 mm further allows stronger gears to be used
- KX450F type crankcase oil filter added
- Relocated scavenge oil filter screen (with new shape) can be accessed without splitting the crankcases, facilitating easier maintenance
- New clutch and generator covers for increased rigidity and better crash survivability
New Aluminum Perimeter Frame
- Frame has a new 6 mm slimmer overall width main spars shape - narrowing near the bend below the seat for a riding position, then widening at the ankles to offer better grip
- Newly designed main, lower and gusset pieces around the fuel tank with revised cross sections
- Rigidity increased by moving upper engine mounts to sides of the head cover
- New design is 2.2 lbs lighter than previous model
- Weight savings and rigidity balance aided by down tube with a smaller cast bracket that’s now formed via a swaging (squeezing and hammering) process
- Swingarm pivot is located higher in the frame for improved rear wheel traction
- Sub-frame is 1.3 pounds lighter via larger diameter tubing with thinner walls, yet still provides a secure mounting for the new silencer
New Aluminum Swingarm
- New tapered "D" shaped cross section design is 5mm taller at the front (up from 74 to 79mm) and 2 mm shorter at the rear (down from 60 to 58mm)
- Features a new cross bracket design
- Provides a 0.9 lbs weight savings over the previous model
- Alloy swingarm uses a cast front section, tapered hydroformed spars and forged chain adjusters
- Uni-Trak rear suspension system mounts the suspension arm below the swingarm, allowing a longer rear suspension stroke and more precise tuning
- Design improves stability, rigidity and rear wheel traction
New Front Fork
- Showa twin-chamber fork keeps oil and air in separate chambers for stable damping performance during long motos
- Super-hard titanium coating on the outer surface of the inner fork tubes reduces stiction and improves suspension action. The increased surface hardness of the dark navy blue coating also helps prevent scratches and damage to the tubes
- Friction-reducing Kashima Coat on the inside of the outer fork tubes contributes to smoother suspension action, especially during the initial part of the stroke
- Ideal rigidity balance via increased rigidity in the reshaped upper triple clamp and decreased rigidity of the outer fork tubes
- Offset decreased from 24.5mm to 23.5mm, which combined with the frame’s revised rigidity balance and revised suspension settings, helps produce lighter handling
- Enlarged, wrap around black fork tube guards provide greater protection for the inner tubes
- Revised race-oriented suspension settings offer all-around performance improvement
New Rear Shock
- New Showa rear shock features a revised layout and revised damping characteristics for improved performance
- Better response and improved feeling, even when fully-bottomed
- Features Kashima Coat on the tank cylinder for reduced friction and smoother suspension action
- Rear shock features dual compression adjustability, allowing high-speed and low-speed damping to be tuned separately
- Easier accessibility for tuning
New Skid Plate
- Resin material offers greater protection without a weight increase
New Chain Guide
- More slim and compact, down from 42.7 to 34mm wide, with 2mm thicker wear pad
- Reduced weight and longer wear
Improved Rider Interface and Styling
- Foot peg width (front to rear) increased from 46mm on previous model to 50mm for improved feel
- All-new body work and graphics
- New dual injected 2-tone, one-piece plastic shrouds and side number plates
- Right side panel has an added passageway to aid in cooling the silencer
- Black plastic covers, triple clamps, number plates, and engine covers
- Rims are coated in black alumite just like the factory racers
- New seat design that’s slimmer with firmer urethane for improved ergonomics and feel
- Seat has a slip-resistant top surface for good grip when seated and smooth sides for excellent rider mobility
- Larger front brake lever boot offers increased protection against dust
- Clutch cable boot features a large quick adjuster, for easy clutch cable play adjustment on the fly
- Throttle grip has a one-piece collar that provides additional stability during throttle operation
- Lightweight short-length grips feature a pattern designed to provide excellent grip
- Rear caliper guard protects the caliper from damage
- Ribless rear hub and butted spokes reduced unsprung weight