Kawasaki enhances the dynamic excellence of its world championship winning KX450F motocrosser with a new five-speed gearbox plus a host of engine and chassis refinements aimed at increasing its domination over the competition.
The 2007 KX450F offers all the dirt-shredding power from last year’s motorcycle, with enhanced bottom end and midrange thrust for even quicker acceleration from the starting gate and stronger drive out of corners. This revised engine tuning is coupled with a new five-speed transmission to allow greater flexibility in gear selection and increase the rider’s options in difficult rhythm sections.
Never one to rest on its laurels, Kawasaki also lavished attention upon the KX450F’s frame and suspension. With reduced frame spar rigidity, new fork internals, and the industry’s first diamond like carbon (DLC) coated fork tubes, the ’07 KX450F boasts improved rear wheel traction and suspension action to improve handling, maximize acceleration and offer easier line selection when passing the competition.
The new KX450F will be available in Kawasaki lime green, with a new colored surface treatment on wheel hubs and engine covers, and aggressive race team graphics.
- 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
- 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
- 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
- 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
- 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
- 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
- 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 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
Engine: Liquid-cooled, four-stroke single with DOHC and four valve cylinder head
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)
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: 13.6 in.
Seat height: 38.0 in.
Dry weight: 220 lbs.
Fuel capacity: 1.9 gal.
Color: Kawasaki Lime Green