2006 Kawasaki KX 450F

Kawasaki, the brand that introduced the motocross world to perimeter frames and awe-inspiring powerbands, has unveiled an all-new flagship in its leading-edge KXâ„¢ motorcycle line.
Every aspect of the 2006 KX450F, from its ultra-powerful four-stroke engine to the trick aluminum frame and suspension, reflects its purpose as a championship-winning race bike.

Kawasaki engineers stressed every detail on the new, liquid-cooled, 449cc four-stroke engine to ensure that it provides maximum power and traction. Featuring double overhead cams, four valves and a Keihin FCR40 carburetor, it combines amazing acceleration with smooth over-rev capability so the rider can use very ounce of its incredible power on the racetrack.

Kawasaki KX 450F

Hand-finished intake ports maximize intake efficiency, while lightweight titanium valves and aluminum valve retainers reduce reciprocating weight for reliable valve control at high rpm. Plus, double valve springs provide stable operation under intense racing conditions. To ensure quick and easy starting, the KX450F features both an automatic compression release and hot start system.

The KX450F utilizes newly designed, high-capacity Denso radiators, which provide superior cooling under racing conditions. With its tightly packed radiator cores and new fin design, the new radiators improve heat dispersion for consistent engine power characteristics and dependability.

Kawasaki KX 450F

The KX450F comes equipped with a tapered titanium exhaust pipe that expands in diameter from 38 to 41mm, contributing to its broad powerband, and the silencer features new, long-fiber packing.

Kawasaki engineers have matched the high-tech engine to a new four-speed transmission. Combined with a manual, multi-disc wet clutch, the four-speed transmission enables the rider to take advantage of the engine’s inherently broad powerband on the racetrack; from accelerating out of turns to high-speed straights, the rider can use the KX450F’s precise throttle control to adjust speed nearly instantaneously. And to protect the underside of the engine and transmission, the KX450F comes with a lightweight aluminum skid place.

The KX450F chassis has been designed to help the rider put the engine’s power to the ground. To do this, Kawasaki engineers combined their experience designing steel perimeter KX frames and techniques used to construct the Ninja® ZX™-10R sport bike chassis to create an all-new aluminum perimeter frame. Comprised of forged, extruded and cast aluminum parts, the strong twin-spar design gives the KX450F optimum balance of torsional and longitudinal rigidity.

Kawasaki KX 450F

The frame was designed so that the center of gravity and key chassis dimensions would work together to enhance the rear tire’s ability to drive the KX450F forward instead of squatting under acceleration. Additionally, the four-stroke engine sits in an upright position within the new frame to further aid overall traction.

Kawasaki then added complementary front and rear suspension to the KX450F. A Kayaba AOS (Air-Oil-Separate) fork keeps oil and air in separate chambers for stable damping performance during long motos. On the rear, the UNI-TRAK® rear suspension system features an alloy swingarm with tapered spars and linkage ratios to maximize traction under acceleration.

Front and rear petal disc brakes provide stopping power for the KX450F. This design not only helps to reduce unsprung weight, but the petal shape of the discs helps to clean the brake pads for more efficient braking performance.

Kawasaki KX 450F

The slim profile of the KX450F frame, two-piece radiator shrouds that leave the upper frame spars exposed, and careful design of the remaining bodywork make the KX450F feel light and narrow beneath the rider.

The KX450F comes with a Renthal aluminum handlebar, while the seat uses a slip-resistant top surface for good grip when seated and smooth sides for enhanced rider mobility. The KX450F also features titanium footpegs and footpeg brackets for reduced overall weight.

Complementing the KX450F’s ultra-high-performance design is aggressive bodywork and graphics.

Kawasaki offers a number of optional parts for the KX450F, including a top mounting clamp for an oversized handlebar, aluminum and steel rear sprockets, solid petal disc brake rotors for wet racing conditions, optional springs for the front fork and rear shock, and a 20-inch front wheel.

Kawasaki KX 450F

Kawasaki KX 450F Specifications

  • Engine: Liquid-cooled, four-stroke single with DOHC and four valves
  • Displacement: 449cc
  • Bore x stroke: 96.0 x 62.1mm
  • Compression ratio: 12.0:1
  • Carburetion: Keihin FCR40
  • Ignition: Multi-map digital CDI with throttle position sensor (K-TRIC)
  • Transmission: Five-speed
  • Rake / trail: 27.1 degrees / 4.6 in.
  • Front suspension / wheel travel: 48mm inverted, Kayaba AOS with DLC coated sliders, 22-position compression and 20-position rebound dampening adjustment / 12.4 in.
  • Rear suspension / wheel travel: UNI-TRAK® linkage system with 22-position low-speed and variable high-speed compression dampening, 22-position rebound dampening and fully adjustable spring preload / 12.4 in.
  • Front tire: 90/100-21
  • Rear tire: 120/80-19
  • Front brake: Semi-floating 250mm petal disc
  • Rear brake: 240mm petal disc
  • Overall length: 86.0 in.
  • Overall width: 32.3 in.
  • Overall height: 50.4 in.
  • Wheelbase: 58.5 in.
  • Ground clearance: 13.58 in.
  • Seat height: 38.0 in.
  • Dry weight: 220 lbs.
  • Fuel capacity: 1.9 gal.
  • Color: Lime Green
  • MSRP: $6,899



  • 449cc liquid-cooled, four-stroke single with titanium valves
  • Revised engine tuning provides stronger low-through mid-rpm performance, with the same championship winning top-end rush

Top End

  • High-acceleration cams with revised timing help the engine rev more quickly
  • Camshaft lobes and tappets feature a soft-nitride surface treatment for long wear and high-rpm reliability
  • Hand-finished surfaces of the polished intake ports improve intake efficiency at all rpm
  • Lightweight titanium 36mm intake and 31mm exhaust valves and aluminum valve retainers reduce reciprocating weight for reliable valve control at high rpm
  • Double valve springs help ensure stable valve operation
  • Screw-type automatic cam chain tensioner with oil pressure spring
  • Revised ignition timing helps boost power
  • Low-friction coating on piston skirt

Bottom End

  • Crankshaft, rotor mass centralization, oil circulation, and ignition timing have been carefully examined to help ensure ideal engine braking characteristics
  • Crankshaft and connecting rod are sintered for additional rigidity
  • Starting
  • Features highly reliable auto-decompression system; the dual-weight centrifugal decompression system fitted to the exhaust cam eases starting, and its simple construction helps to ensure reliability
  • Hot start system gives quick starts when the engine is hot, and the hot start lever is unitized with the clutch lever


  • Larger 41mm titanium exhaust header for increased power
  • Tapered exhaust pipe joint helps increase ultra-low rpm power.
  • Titanium exhaust pipe heat shield
  • Silencer uses long-fiber packing for lower maintenance


  • High-capacity Denso radiators deliver superior cooling efficiency
  • Slim radiators feature tightly packed cores and fins designed to enhanced heat dispersion


  • New 5-speed Transmission offers better choices for dealing with tough rhythm and tight technical track sections
  • New ball bearing shift lever for smoother shifting
  • Revised ratchet-type shift mechanism for smoother shifting and a more positive feel


  • Frame is wider at the rider’s ankles, for better grip and narrower around the seat for a slim riding position and enhanced maneuverability
  • Modifications to the main frame spars reduce torsional rigidity for quicker turning and lighter steering
  • All-aluminum perimeter frame is a composite structure comprising forged, extruded and cast components
  • The slim profile of the KX450F frame, two-piece radiator shrouds that leave the upper frame spars exposed, and careful design of the remaining bodywork make the KX450F feel light and narrow beneath the rider
  • Aluminum skid plate

Front Suspension

  • New ultra-smooth DLC (Diamond Like Carbon) coating on the fork sliders reduces stiction for better suspension action
  • Kayaba AOS (Air-Oil-Separate) fork keeps oil and air in separate chambers for stable damping performance during long motos
  • Larger front fork damper cartridges with revised valving for a more progressive and plush action
  • Revised fork seals and Inner liners to complement the new DLC coated sliders and reduce stiction

Rear Suspension

  • UNI-TRAK® rear suspension system features revised shock valving to maximize traction for better acceleration and enhanced controllability
  • Revised high speed compression valving in the rear shock provides smoother action in the initial part of the stroke but offers firmer damping rates near full compression
  • Alloy swingarm uses cast front section, tapered hydroformed spars and forged chain pullers; the tapered spars are shaped to match the balance of flex and rigidity required of the aluminum frame.
  • New sprocket style chain roller reduces drive lash


  • Front and rear petal disc brakes help reduce unsprung weight
  • Disc shape helps clean the brake pads for more efficient braking performance


  • 32-spoke rear wheel for reduced unsprung weight
  • Lighter and stronger rear hub for increased durability and less unsprung weight

From the Cockpit

  • Renthal aluminum handlebars are standard
  • Lightweight short-length grips feature a special pattern to reduce vibration transmitted from the bars to the rider
  • Revised front brake master cylinder hose joint allows more lever position adjustment
  • Seat uses a slip-resistant top surface for good grip when seated and smooth sides for excellent rider mobility

Weight Savings

  • Aluminum parts used instead of steel, including clutch cable elbow, clutch cable fitting nuts, fuel tank fitting nuts, seat mounting brackets, front brake hose clamp and igniter stay bracket

New Styling

  • New graphics and seat cover have aggressive style that emulates Kawasaki’s race bikes
  • Number plates now feature graphical highlights for a bolder appearance
  • New colored surface treatment on wheel hubs and engine covers


  • Different weight magneto rotors (+/-1 kg.cm2)
  • Handlebar Holder for a 28.6 mm bar (STD: 22.2 mm)
  • Aluminum and Steel Rear Sprockets (+/-2T)
  • Solid Petal Brake Rotors for wet races
  • Different Rate Fork and Shock Springs
  • 20” Front Wheel
  • Manual Decompression Lever & Cable


im a heavy rider 250lbs what would the correct settings be for the suspension front and rear for my 450f. ive also put on a heavier flywheele for enduro riding is this recomended

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