Introduction
The KX250 motorcycle represents the epitome of Kawasaki's two-stroke
motocross development, and it arrives for 2005 with major revisions
to the engine and chassis, resulting in more power and better
handling to help keep KX250 racers at the head of the pack.
Kawasaki engineers began by creating an all-new Kawasaki Integrated
Power Valve System (KIPS®) for the liquid-cooled 249cc two-stroke
engine. Previously, the main and sub valves operated simultaneously,
causing a power surge after a slight gap in the 6,000 to 7,000
rpm range. By having the valves operate independently, the sub
valves begin to open only after the main valve is fully open.
Power comes on more smoothly, resulting in a more linear powerband,
improved traction and overall more tractable power characteristics.
Plus, the cylinder's forward mounting angle has been reduced
from 10 degrees to five degrees, which allows for the use of
a longer exhaust port, further enhancing power across the rev
range.
The engine's coolant passageways within the cylinder are also
redesigned for improved cooling, particularly around the exhaust
port, to prevent heat-induced power fade during long motos.
The most significant modification to the lightweight steel perimeter
frame is a decrease in steering rake from 27 degrees to 26 degrees,
which quickens steering response for superb cornering performance.
The frame's stiffness balance has also been improved, and a new
lower swingarm bracket improves ground clearance.
While the design of the aluminum swingarm remains unchanged,
the wall thickness of the main spars is increased for enhanced
stability and handling.
Changes to the front suspension include new twin-chamber Kayaba
forks, which help to keep oil and air separate for stable damping
performance during long motos, and low-friction fork seals contribute
to smoother action. In addition, the new UNI-TRAK® rear suspension
system features redesigned linkage ratios to suit the new frame
and swingarm.
The revised frame is narrower at the footpegs, giving the bike
a slimmer feel, and higher footpegs complement the new riding
position while increasing ground clearance. The rear brake pedal
is also mounted 15mm higher for increased ground clearance, and
to suit the new riding position.
Other ergonomic changes include a revised handlebar bend, which
contributes to improved rider mobility, and a new seat that is
flatter and raised 10mm higher for improved rider mobility. The
seat cover also uses a high-grip top and smooth sides for good
grip when sitting and high mobility when standing on the pegs,
while more durable urethane foam improves comfort and wear.
For 2005, Kawasaki's trademark Lime Green bodywork is more vibrant
than ever before, so the KX250 rider stands out in the crowded
starting grids and race tracks.
Those who race their KX250 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, 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
Engine
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Numerous refinements to the liquid-Engine/Transmission
- Head gasket changed from metal gasket to O-rings for improved
sealing and more accurate deck height
- New intake design features a single port with modified length
and angle for improved intake efficiency
- Scavenging port exit angle is changed for improved scavenging
efficiency, and the crankcase mating area around the scavenge
ports has been increased. Third scavenging port also modified
for improved flow
- New reed valve angle, air guide and reed block are changed
for improved throttle response
- Intake air duct is reshaped to suite revised intake manifold
- New expansion chamber dimensions and improved construction
(changed from four-piece to a three-piece) contributes to improved
engine performance
- Redesigned piston uses new rings and new piston sealing grooves
to prevent ring snagging; stronger pin boss improves durability
- Clutch release shaft and lever modified, and release mechanism
moved behind generator cover
- Shift performance improved by using involute splines on the
fifth gear and on the output shaft. A needle bearing added to
the shift shaft improves shift feel
- New water pump uses new pump gear ratios and a new impellor
for increased coolant circulation, plus a new water jacket around
the exhaust port eliminates the need for an external coolant
hose
- Sprocket cover, governor cover, inner/outer clutch covers,
and water pump cover changed to suit new crankcases
- Generator cover changed from plastic to magnesium for improved
appearance and increased functionality
- Revised carburetor settings contribute to improved throttle
response, and a new carb holder allows straighter incoming airflow
- Radiator core length increased (from 220 to 240 mm) for improved
cooling performance
- Upgraded ignition system features increased condenser capacity
and a generator with a built-in regulator for light weight. Stator
shape changed, and new wiring harness used. Ignition timing changed
to suit new power characteristics
- New, shorter spark plug eases maintenance and weighs less
- New, lightweight ignition coil is more compact
- Ignition coil primary terminals feature waterproof couplers
for increased reliability
- Low-friction throttle barrel also reduces throttle operating
friction
Rider Controls
- Stainless throttle cable wire with a greater number of thinner
strands delivers superb, low-friction throttle operation
- Clutch cable outer liner changed from polyethylene to Teflon
for reduced friction
- Clutch adjuster added to clutch lever perch
- New front brake lever has better feel
Chassis/Suspension
- Steering rake reduced to 26 degrees to quicken steering response
- Footpegs are wider and offer better grip; shorter transverse
length means greater cornering clearance
- Wider handlebar mounts (increased from 90 to 98 mm) help prevent
handlebar bending
- New lightweight DID front rims with lightweight spokes and
nipples reduce unsprung weight
- New cross-section for rear rims also designed for light weight
- Light fork and shock mounting bolts and a new rear brake master
cylinder with a unitized reservoir and shorter yoke (17.5 mm
shorter than '04 KX250) contribute to light weight
- Fork mounting bolt locations changed on the top triple clamp
for easier maintenance and stronger mounting
- New front brake pad material offers better feel and performance
- Chain guide roller now uses two bearings for greater durability
- Rear subframe has larger forged upper mounting brackets for
improved durability
- Fuel tank filler outlet is increased form 37 to 46mm for easier
fueling
Options
- Carburetor tuning parts
- Ignition rotors with different inertial weights
- Larger 14T front sprocket
- Spark plugs of varying heat ranges
- 20-inch front wheel
- Solid brake discs
- Aluminum and steel rear sprockets
- Different fork and shock springs
- Steel spoke nipples
- Front and rear wheel assemblies
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Technical Specifications
Engine
Two-stroke single with KIPS®
Displacement: 249cc
Bore x stroke: 66.4 x 72.0mm
Cooling: Liquid
Carburetion: Keihin PWK38S with Power Jet
Induction: Piston reed valve
Compression ratio: 10.5 (low speed) 9.1 (high speed):1
Ignition: Digital CDI
Transmission: Five-speed
Chassis
Frame: Perimeter style, high-tensile steel with aluminum subframe
Rake/trail: 26 degrees / NA
Suspension type, front: 48mm twin chamber inverted cartridge-type
telescopic fork
Suspension adjustments, front: 16-way compression and rebound
damping
Suspension type, rear: New UNI-TRAK® swingarm, single shock
Suspension adjustments, rear: 16-way compression and rebound,
threaded preload
Wheel travel, front: 11.8 in.
Wheel travel rear: 12.2 in.
Tires/Brakes
Tire, front: 80/100 x 21
Tire, rear: 110/90 x 19
Brakes, front / rear: Hydraulic disc
Measures/Weights
Overall length: 86.0 in.
Overall width: 33.1 in.
Overall height: 49.8 in.
Ground clearance: 13.4 in.
Seat height: 38.0 in.
Dry weight: 213.8 lb.
Wheel base: 58.3 in.
Fuel capacity: NA
Color
Kawasaki Lime Green 
* Price and specifications subject to change
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