Off-Road.com's Ride-Net! 2002 Kawasaki Dirt Bikes - KX 250

Feb. 01, 2006 By ORC STAFF

KX250
   


2002 KAWASAKI KX250

The 2002 model incorporates a full complement of engine modifications and chassis alterations. With its potent two-stroke single-cylinder 249cc engine, Kawasaki focused on increasing throttle response and improving power throughout the rev range. They achieved this in part by reshaping the exhaust port and modifying the exhaust- and scavenging-port timing.

 

A new two-piece exhaust powervalve replaces the old three-piece butterfly unit, and valve width was increased. The exhaust pipe was fitted with thicker O-rings, as well as a longer retention spring and a plate where the pipe mounts.

Another significant modification to the engine is that the twin-spark ignition features overlapping twin sparks through the midrange, and a new 16-bit processor for improved low-end power.

For added engine durability, the connecting rod was given a smoother finish. Also, an oil groove at the big end of the con-rod was enlarged, there's increased crowning to the big-end bearings ad the edges of the side washers so oil flows more freely. The diameters of the main bearings were increased, as was the kickstart shaft.

A tooth was added to the primary gearing, and left and right crank cases were modified to maintain clearance between the connecting rod and cases. Power is delivered to the rear wheel via a smooth-shifting five-speed transmission whose second through fifth gear ratios were revised for better and smoother power delivery. Also, gear tooth valleys were redesigned for increased contact area.

A compact, high-tensile steel perimeter frame with new solid-mounted footpegs supports the KX250. Up front, the fully adjustable fork was increased in diameter, while tube thickness was decreased. The upshot is increased rigidity with less weight.

 

Rear suspension is handled by Kawasaki's UNI-TRAK® linkage system that progressively increases damping and spring rates on the fully adjustable rear shock as the suspension is compressed. For '02, the system was revised with longer pull rods and new rocker dimensions for a new linkage ratio that improves performance, especially near bottoming.

Rounding out the KX250's enhancements are taller, straighter handlebars, an aluminum clutch-cable adjuster, reshaped saddle with thicker foam and a base that increases air flow around the airbox. The already-flat fuel tank is even flatter for '02, and incorporates new square inset nuts where the shrouds and seat base mount for more security. New side covers complement the new seat and tank, as do new thicker graphics.


FEATURES:

  • Liquid-Cooled Engine with Kawasaki Integrated Power Valve System
  • Reshaped porting for more power throughout the rev range and better over-rev power
  • New two-piece powervalve with increased valve width, and new spring and lever shape for better sealing and increased mid-range power
  • Piston skirt lengthened for better exhaust-port sealing Keihin Power Jet PWK38S

Carburetor with K-TRIC

  • "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 a fuel passageway according to rpm and throttle position for crisp jetting and increased top-end power at over-rev

Exhaust System

  • O-rings are thicker, retention spring is longer and a plate was added to the exhaust pipe mount for better sealing

Five-Speed Transmission

  • Second through fifth gear ratios changed for better and smoother power delivery
  • Gear tooth valleys changed from rounded to squared for increased contact

Crankshaft

  • Primary gear was altered to complement new transmission gear ratios

Connecting Rod

  • Redesigned to allow more oil into the big-end bearing for improved durability
  • Features connecting rod with a smoother finish for unimpeded oil flow

Crank Cases

  • Increased outer diameter of main bearing
  • Increased diameter of kickstart shaft, which is now mounted on an involute spline
  • Crank case modified and outer diameter of the bearing increased to maintain clearance between connecting rod and cases
  • Governor assembly and spring modified to complement gear ratio modifications and larger kickstart shaft

All-New Twin Spark Ignition System

  • Produces two overlapping sparks for longer intervals at lower rpm for improved power and torque from ultra-low rpm through the mid-range
  • New iridium sparkplug increases spark energy to enhance performance and over-rev
  • New 16-bit processor accommodates new system and modified ignition timing
  • Rotor incorporates vent holes to improve cooling

UNI-TRAK® Rear Suspension

  • Cast-aluminum section of the swingarm is designed for less unsprung weight and more rigidity
  • The shock features both low- and high-speed compression-damping adjustments
  • 48mm Upside-Down Cartridge Fork
  • Inner fork tube diameter increased for more rigidity
  • Tube thickness decreased for weight loss

Front and Rear Disc Brakes

  • Front brake caliper's twin pistons made from aluminum to reduce weight
  • Rear brake master cylinder incorporates new push rod for improved pedal position

High Tensile Steel Perimeter Frame.

  • Features new footpegs to reduce mud build-up.
  • Removable aluminum rear sub-frame for easy access to the rear shock

Details

  • New graphics
  • Reshaped seat to increase airflow around airbox
  • Flatter fuel tank incorporates new square inset nuts where the shrouds and seat base mount for security
  • Revised side covers complement new seat and tank
  • New handlebar bend is 10mm taller and 10mm straighter
  • New chain and chain roller with bearing to reduce weight and increase durability
  • Optional 20-inch rim or wheel assemblies available
  • Aluminum clutch cable adjuster replaces old steel unit to reduce weight

SPECIFICATIONS:

KX250
Engine: 2-stroke single w/KIPS
Displacement: 249cc
Bore x Stroke: 66.4 x 72.0mm
Compression Ratio: 10.5:1 (low speed), 8.9:1 (high speed)
Cooling: Liquid
Carburetion: Keihin PWK38S with Power Jet and K-TRIC
Induction: Piston reed valve
Ignition: Twin Spark Digital CDI
Transmission: 5-speed
Frame: High-tensile steel perimeter design with aluminum subframe
Rake/trail: 26°/4.3 in.
Suspension type, front: Inverted telescopic cartridge fork, 48mm
Suspension adjustments, front: Preload, 18-way compression and rebound damping
Suspension type, rear: UNI-TRAK® single shock system
Suspension adjustments, rear: Preload, 3-turn high and 20-way low speed compression and 18-way rebound damping
Wheel travel, front: 11.8 in
Wheel travel, rear: 13.0 in.
Tire, front: 80/100x21
Tire, rear: 110/90x19
Brakes, front/rear: Hydraulic disc
Overall length: 85.6 in.
Overall width: 32.1 in.
Overall height: 47.6 in.
Ground clearance: 15.0 in.
Seat height: 37.4  in.
Dry weight: 213.9 lb.
Fuel capacity: 2.25 gal.
Wheelbase: 58.3 in.
Color: Lime Green


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