Introduction
Factory-style components and tuning
for every racer
Kawasaki's KX'250F motocrosser had a victorious year, winning
on the track and topping its class in numerous enthusiast magazine
shootouts. The successful mix of the highly rigid aluminum frame
and top-shelf suspension components deliver superb high-speed
stability, while its chassis geometry and high-revving engine
offer excellent rear wheel traction and holeshot-winning performance.
Christophe Pourcel used his new Monster Energy/ Pro Circuit /
Kawasaki KX250F to win the AMA East Supercross Lites Championship
and then continued his winning ways into the outdoor season.
But in the volatile world of racing, it's a constant challenge
to stay on top.
To ensure it continues its podium-topping tradition, Kawasaki
fine-tuned the light handling KX250F for 2010. The engineers
capitalized on its solid foundation, with refinements focused
on increasing performance and longevity. The result of their
labors will help the KX250F add to its ever-growing trophy collection.
Borrowing from the racing world, the KX250F gets a new piston
with a bridged-box bottom making its first appearance in a mass-production
machine. The new piston is lighter and stronger. It also has
a revised profile with a shorter skirt and shorter piston pin,
which reduces reciprocating weight. It also features a revised
crown that improves combustion. The cylinder height was raised
accordingly to maintain the 13.2:1 compression ratio. Low-rpm
performance was bumped up via a new longer head pipe and shorter
mid-section on the new, more durable stainless steel exhaust
pipe.
The 249cc, liquid-cooled, four-stroke engine received a number
of other refinements for 2010, such as electrofusion treatment
on the cylinder bore, revised oil pump rotors and a wider big-end
bearing to increase engine life.
Its crank web design produces a crankshaft balance factor of
close to 60 percent, on par with Kawasaki's factory racers. The
result is reduced engine vibration, smoother power delivery and
increased performance in the mid-high rpm range. Tuned to deliver
the widest possible torque band, the KX250F engine offers traction
in a controllable, class-leading manner from the first crack
of the throttle to wide-open at the rev limiter.
Like its bigger sibling, the KX250F received larger, stronger
radiators with increased fin and tube pitch that accumulate less
mud and provide more consistent cooling. With the extra strength
in the new radiators, the reinforcing brackets could be dropped,
helping reduce the weight of the entire radiator assembly.
Transmission durability was also raised inside and out. Building
upon the achievements of last year, Kawasaki engineers put larger
dogs on the third and fourth input gears to help prevent wear,
and revised the fourth input gear holding method by eliminating
a circlip and washer and changing the shape of the second input
gear to reduce thrust clearance. On the outside, the new KX250F
crankcases are stronger and thicker with increased material around
the engine mount holes. The transmission action and feedback
are optimized with its ratchet drive shift mechanism and integrated
clutch cable holder into the crankcase.
With its lightweight construction blend of forged, extruded and
cast parts, the KX250F's slim aluminum perimeter frame has the
chassis balance and settings race-experienced riders seek. The
center of gravity and locations of key items such as the swingarm
pivot, output sprocket and rear axle were positioned to best
channel the drive from the rear tire into forward acceleration.
For 2010, chassis improvements are primarily focused on delivering
sharper cornering performance and an optimized front-to-rear
balance for improved suspension composure. To achieve this balance,
the race-oriented suspension settings were revised for a more
balanced less forward-leaning chassis posture when riding. A
new steering stem with lower rigidity helps lighten handling,
while also providing smoother fork action and better impact absorption.
These revisions refine the stable damping performance of the
KX250F's Showa twin-chamber fork during long motos and work in
conjunction with the updated swingarm, which features a modified
cross-section with thinner wall thickness and narrower internal
ribs. The Showa rear shock's new damping settings provide greater
stability and less "kicking" on corner entry. New Uni-Trak
rear suspension linkage ratios match these new rear shock damping
characteristics.
Designed with rider ergonomics in mind, the KX250F bodywork offers
riders a slim interface and a natural positioning that make it
easier to go fast. The sleek bodywork components include one-piece,
dual injected, two-tone black and green plastic shrouds and side
number plates. The shrouds were fine-tuned to fit the new radiators
while retaining their slender form. For 2010, a thicker and more
rigid front fender graces the KX250F. The slim, rider friendly
seat with a non-slip top surface and smooth sides provides excellent
seated grip and rider mobility, and gets firmer urethane foam
to hold its shape longer.
Chassis protection is grade-A for 2010, and helps sustain the
KX's durability factor. Examples include the large, resin skid
plate, the rear caliper guard and the narrow, long-lasting chain
guide, all of which offer protection without high weight.
The rest of the KX250F is equally impressive, with premium-quality
Renthal aluminum handlebars included as standard equipment along
with black triple clamps, engine covers and hubs. The new black
alumite coated lightweight aluminum wheels feature a revised
cross section that offers both increased strength and lighter
weight, and the ribless rear hub and butted spokes further reduce
unsprung weight. Factory-style graphics finish off the package
and complement the KX250F's stellar on-track performance.
Racers who ride their KX250F at designated events are eligible
to receive support from Team Green, Kawasaki's amateur racing
support program. Each year, Team Green provides regional support
vehicles and highly trained technicians at more than 100 events
throughout the United States, offering technical information
and assistance to those who race Kawasaki products. Kawasaki
also offers a comprehensive contingency program for amateur and
professional riders who place well at designated events.
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Features
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
Better Cooling
- 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
Improved Transmission
- 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
Additional Features
- 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
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Technical Specifications
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
Frame: Aluminum perimeter
Rake / trail: 27.4 degrees / 4.7 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: 231.4 Lbs.
Fuel capacity: 2.1 Gal.
Color: Lime Green
MSRP: $6,999
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