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.
2007 Kawasaki KX450F
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
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
Exhaust
Larger 41mm titanium exhaust header for increased power
Silencer uses long-fiber packing for lower maintenance
Cooling
High-capacity Denso radiators deliver superior cooling efficiency
Slim radiators feature tightly packed cores and fins designed to enhanced heat dispersion
Shifting
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
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
2007 Kawasaki KX450F
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
Brakes
Front and rear petal disc brakes help reduce unsprung weight
Disc shape helps clean the brake pads for more efficient braking performance
Wheels
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
Engine: Liquid-cooled, four-stroke single with DOHC and four valve cylinder head 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: 13.6 in. Seat height: 38.0 in. Dry weight: 220 lbs. Fuel capacity: 1.9 gal. Color: Kawasaki Lime Green MSRP: $6,899