2007 Kawasaki KX450F
General Specifications
| Model | KX450F |
| Year | 2007 |
| Category | Motocross |
| Engine Type | 449 cc liquid-cooled DOHC 4-stroke single-cylinder, 4 valves |
| Weight | 99.8 kg dry |
Engine
| Displacement | 449 cc |
| Bore x Stroke | 96.0 x 62.1 mm |
| Compression Ratio | 12.0:1 |
| Fuel System | Keihin FCR40 flat-slide carburettor | Replacement Options |
| Ignition | Digital AC-CDI |
| Spark Plug | NGK CPR8EB-9 |
| Spark Plug Gap | 0.8-0.9 mm |
| Cooling System | Liquid cooled |
| Starting System | Kick start |
Transmission
| Transmission | 4-speed constant mesh, return shift |
| Clutch | Wet multi-disc manual |
| Final Drive | Chain |
Dimensions
| Overall Length | 2185 mm |
| Overall Width | 820 mm |
| Overall Height | 1280 mm |
| Wheelbase | 1485 mm |
| Ground Clearance | 345 mm |
| Seat Height | 965 mm |
| Fuel Capacity | 7.2 L |
Chassis
Suspension
| Front Suspension | 48 mm Kayaba inverted AOS telescopic fork, adjustable compression and rebound damping | Fork Oil Levels |
| Front Suspension Travel | 315 mm |
| Rear Suspension | Kayaba New Uni-Trak linkage shock, adjustable spring preload, compression and rebound damping |
| Rear Suspension Travel | 315 mm |
| Fork Oil | KHL15-10 (Kayaba 01) or equivalent; 355 ml outer chamber and 191 ml inner/subtank per fork leg | Fork Oil Levels |
Brakes & Wheels
| Front Brake | 250 mm single hydraulic petal disc, twin-piston caliper |
| Rear Brake | 240 mm single hydraulic petal disc, single-piston caliper |
| Front Wheel Size | 21 inch |
| Rear Wheel Size | 19 inch |
Service Data
| Fuel Type | Premium unleaded petrol |
| Premix Information | Not applicable - 4-stroke engine |
| Gearbox Oil | Engine and transmission share the same oil supply; SAE 10W-30, 10W-40 or 10W-50, API SG/SH/SJ or SL, JASO MA; approximately 0.96 L oil change, 0.98 L with filter change, 1.2 L when completely dry |
| Air Filter | Washable oiled foam element |
| Service Notes | Competition motocross model requiring frequent engine-oil changes, air-filter servicing and valve-clearance inspection |
2007 Kawasaki KX450F: Refining Kawasaki's Big Four-Stroke
The 2007 Kawasaki KX450F was the second production year of Kawasaki's 450 four-stroke motocrosser, so it represented an evolution of the original 2006 machine rather than an entirely new generation. The basic ingredients remained familiar: a 449 cc DOHC four-stroke single, Keihin FCR carburettor, aluminium perimeter frame, Kayaba suspension and Kawasaki's unusual four-speed transmission.
That four-speed gearbox remained one of the KX450F's most distinctive features. Kawasaki relied on the engine's broad spread of torque rather than adding another ratio, giving the early KX450F a character quite different from many of its five-speed rivals. The carburetted engine also places the 2007 firmly in the first generation of modern 450 motocross machines, before electronic fuel injection became the class standard. Owners maintaining the original fuel system can use the MXOwners carburettor reference and replacement information when researching worn or replacement components.
Kawasaki continued with 48 mm Kayaba AOS forks and its New Uni-Trak rear suspension system, providing approximately 315 mm of travel at each end. The 2007 fork specification differs from the first-year machine in oil quantity, making correct model-year information important during a rebuild. Owners servicing the suspension can consult the MXOwners fork oil reference for additional setup information.
By 2007 the KX450F was also firmly established as Kawasaki's premier-class factory race bike. James Stewart was one of the riders most closely associated with Kawasaki's move from the KX250 two-stroke to the big four-stroke, helping establish the KX450F name at the highest levels of American motocross and Supercross during this period.
For today's owner, the 2007 KX450F remains an interesting example of the early 450 four-stroke era: powerful, carburetted, kick-started and mechanically less complicated than the fuel-injected machines that followed. Because Kawasaki developed the KX450F rapidly during its early years, parts should be checked against the exact model year rather than assuming interchangeability with later bikes. The MXOwners parts finder can help when researching replacement components.
