The 2003 Kawasaki KX250 motorcycle has emerged as a completely new machine - engineered to showcase technical prowess, exceed expectations and surface as a force to be reckoned with amongst its competitors. From the design table to the test track, the development of a championship motocross bike focuses heavily on performance. The completely revamped KX250 proudly boasts significant engine upgrades and the first comprehensive exterior design since 1999.

Although the KX250 already features one of the broadest powerbands in its class, Kawasaki still focused on refining the engine's low-rpm response, torque range and over-rev, resulting in a more linear, smoother and wider powerband. An all-new cylinder - featuring chrome-composite plating, a first for the KX series - and new straight-edge exhaust porting contribute to the improved engine characteristics, as do several modifications to the Kawasaki Integrated Power-valve System (KIPS3) timing. Stronger and larger radiators improve cooling capacity and new exhaust pipe dimensions, mated to a 20mm shorter exhaust system, contribute to improved midrange and top-end power.

To make the best use of the new power, second and third gear ratios have been changed and are controlled by a new ratchet-type shift mechanism. Tightened tolerances between shafts and gears also make shifting more precise. To accommodate the new ratchet shifter, the clutch and clutch housing were made over, receiving a longer push rod and lighter feel. To keep the clutch and transmission lubed appropriately, an oil hole and cavity was added to the transmission input shaft. All of these engine and transmission improvements complete the extensive package of modifications and make the engine not only powerful, but extremely user friendly.
The highlight of the new chassis is the new generation Kawasaki perimeter frame, that brings in an all-new era in KX250 handling. The KX250's cornering ability was made more precise by steepening the rake one-degree and moving the offset of the fork tripleclamp 3mm forward, creating a new, more comfortable riding position. Raised chassis ridges reduce boot wear and eliminate plastic rubbing plates. Giving the new frame a factory race appearance is its aircraft gray painted finish and stealthy sleek lines.

To accommodate the balance of the new frame, the 48mm Kayaba fork has been completely revamped, eliminating the bladder system to provide more responsive fork action. Out back, a revised UNI-TRAK3 rear suspension system received a new tapered aluminum hydroformed swingarm, precisely balanced with the chassis and attached to a new lighter and easier to service linkage system. A new KYB shock with a spring rate of 5.1 kg completes the updated UNI-TRAK system. The shock's high/low speed compression adjuster was eliminated and replaced by a single compression adjuster that allows for a free-flowing shock action.

A new rear-wheel hub supports a 5mm larger diameter rear axle, which matches the stronger swingarm and chassis. Laced to both front and rear hubs is the popular oval style rim (new on the KX250) that debuted on the 1999 KX125. Bridgestone 601 and 602 tires clad the new rims and provide optimum traction. Giving the KX250 precise braking is a new one-piece design rear master cylinder, which improves reliability and reduces maintenance. The rear brake rotor also went through a change, thinning 5mm and growing 20mm larger in diameter, for lighter weight and more braking power. All chassis improvements contribute to enhanced cornering performance with a plusher ride, reduced weight and a better overall ride quality.

Naturally, all new bodywork and graphics grace the new machine - from the front fender to the rear and everything in between, including the seat and fuel tank. Although the smoother exterior design and radical graphics package give the KX250 an exciting new look, there will be no mistaking it for anything other than a Kawasaki.

All KX motorcycles come with the support of Team Green, Kawasaki's amateur support program. Each year, Team Green attends more than 100 events across the country, providing regional support vehicles and highly trained technicians to provide technical information and assistance for anyone who rides or races a Kawasaki. Team Green also offers a comprehensive contingency program for amateur and professional riders who place well at designated events. Team Green, the most successful amateur support program in off-road and motocross racing history, boasts a remarkable list of championship-winning alumni and celebrates its 21st anniversary in 2003.

Features

• Low rpm response improved and torque range broadened
  
• Better over-rev characteristics with smoother, wider powerband
  
• Oil groove in left case for lubrication of clutch mechanism
  
• New crank bearings with thicker inner races for improved durability
  
• Main bearing diameter increased at inside and outside 2mm
  
• Clutch cover made of magnesium alloy to reduce weight

Cylinder Head:

• Combustion chamber shape changed to create more power on top and better over-rev
  
• Compression ratio revised from 8.9:1 to 8.6:1
  
• Head mount reversed to match chassis
  
  Cylinder:
  
• Special chrome composite plating lines cylinder walls, providing improved surface quality
  
• Upper exhaust port edge straightened, for better power
  
• Increased mid-range and top-end power
  
• Carburetor manifold mount 10mm higher, eliminating carburetor interference with center cases
  
• Unpainted cylinder depicts raw, race-like appearance
  
• Kawasaki Integrated Power-valve System (KIPS3):
  
• New KIPS timing follows rpm more accurately
  
• Straight-edge exhaust port enhances KIPS
  
• Valve shape modified to match new engine port
  
• Exhaust gases flow smoothly, resulting in more mid-range and top-end power
  
• KIPS opens sooner over greater rpm range, reacting to throttle quicker
  
• Keihin Power Jet PWK38S Carburetor:
  
• Shorty design places the main jet and slide close to the cylinder for improved throttle response
  
• Kawasaki Throttle Responsive Ignition Control (K-TRIC) uses a sensor to alter ignition timing according to throttle position and engine speed for better throttle response and more power
  
• Power Jet system uses an electronic solenoid to close fuel passageway according to rpm and throttle position for crisp jetting and increased top-end power at over-rev
• Reed Valve:
  
• Reed valve air guide redesigned with vertical cross-hair added, resulting in improved engine response
  
• Redesigned air guide improves reed durability
  
• Exhaust System:
  
• Muffler 20mm shorter, resulting in lighter weight and improved mid-range and top-end power

Five-Speed Transmission:

• Involute spline clearances are reduced
  
• Tolerances closer between shafts and gears, making shifting more precise
  
• Oil hole added to input shaft resulting in improved transmission durability
  
• Wider ratio between second and third gears matches new engine powerband
  
• Clutch:
  
• Push rod lengthened and rod actuator shape changed to improve clutch feel
  
• One-piece washer/collar clutch bushing makes for easy maintenance
  
• Clutch housing shape changed to accommodate new ratchet shifting system
  
• Ignition System:
  
• New single spark-ignition with acceleration compensator shares same advantages as previous twin-spark ignition
  
• Detects each crankshaft revolution for quicker ignition response, while Twin Spark detected every other evolution
  
• New ignition map suits revised power characteristics
  
• Kawasaki Throttle Responsive Ignition Control (K-TRIC) maximizes ignition timing advance
  
• Head pipe ignition mount mirrors KX125

UNI-TRAK Rear Suspension:

• Revised linkage ratios provide better action and reduce ride height by 10mm for lower center of gravity
  
• Shock features compression and rebound damping adjustments
  
• Swing arm hydroformed in tapered shape to increase strength and stiffness while lowering weight
  
• Pull rod redesigned with width increase
  
• 48mm Upside-Down Cartridge Fork:
  
• Fork offset increased from 22 to 25mm for sharper cornering performance
  
• New damping mechanism eliminates bladders
  
• Bump rubbers replace the oil-lock method, improving bottoming characteristics
  
• New oil level and fork tubes raised 10mm in tripleclamps, improving fork action

Triple Clamps:

• Thinner wall thickness reduces weight
  
• Steering shaft 6mm longer to match longer steering head pipe
  
• Top tripleclamp pinch bolts thread from rear, eliminating interference with number plate
  
• Aluminum steering stem tapered to reduce weight
  
• Front and Rear Disc Brakes:
  
• Dual-piston front brake caliper uses 27mm pistons, operated by 11mm master cylinder piston
  
• Rear master cylinder now one-piece design, improving durability
  
• Rear rotor diameter and thickness changed from 220 x 4.5mm to 240 x 4.0mm, resulting in more braking power
  
• Rotor bolts now 8mm stepped type to ease maintenance and improve liability
  
• New brake pad material improves performance and feel
  
• New Generation Kawasaki Perimeter Frame:
  
• New chassis compact and quick handling
  
• Rake one-degree steeper to aide cornering ability
  
• Head pipe 6mm longer to accommodate chassis' larger perimeter tubes
  
• Single top bolt used to attach aluminum rear subframe for easy access to the rear shock
  
• Color change from green to gray gives frame a raw factory appearance
  
• Raised chassis ridges reduce boot wear
  
• Styling and Bodywork:
  
• All-new styling and bodywork includes front and rear fenders, tank, seat, side
  covers and front number plate
  
• Exterior design smoother for improved rider mobility
  
• Reshaped radiator shrouds make it easier for the rider to move about the bike
  
• Thicker clear coating for new graphics increase durability
  
• Seat features new shape for improved comfort and increased mobility

Details:

• Bridgestone-clad oval-type rims new to KX250
  
• Shares many common parts with 2003 KX125
  
• Rear axle diameter increased from 20mm to 25mm to match stronger swing arm
• New rear hub incorporates 25mm axle
  
• Radiator capacity increased resulting in improved cooling
  
• Handlebar bend with smaller diameter grips is slightly higher and pulled back tosuit new chassis
  
• Optional 20-inch front wheel assemblies available
  
• Optional front disc brake rotor guard

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