| MODEL | YAMAHA WR 450F 2003 - 2004 |
| Year | 2003 - 2004 |
| Engine Type | Four stroke, single cylinder, DOHC, 5 titanium valves |
| Displacement / Capacity | 449 cc / 27.4 cu in |
| Bore X Stroke | 95 x 63.4 mm |
| Compression Ratio | 12.5:1 |
| Cooling System | Liquid cooled |
| Max Power | 42.3 kW / 58 hp @ 9000 rpm |
| Max Torque | 49 Nm / 33.1 lb-ft @ 7000 rpm |
| Ignition | Digital CDI |
| Induction | 39 mm Keihin FCR flat-slide carburettor with throttle position sensor |
| Start System | Electric and kick |
| TRANSMISSION SPECS | |
| Lubrication | Wet sump |
| Gear Box | 5 speed |
| Clutch | Wet, multi-disc, cable operated |
| Final Drive | O-ring chain |
| CHASSIS SPECS | |
| Frame | Steel, single cradle |
| Front Suspension | 46 mm Kayaba inverted telescopic fork, compression and rebound damping adjustable, 300 mm / 11.8 in travel |
| Rear Suspension | Fully adjustable Kayaba single shock, 318 mm / 12.4 in travel |
| Front Brakes | Single 250 mm disc, 4-piston caliper |
| Rear Brakes | Single 245 mm disc, 2-piston caliper |
| DIMENSION SPECS | |
| Overall Length | 2175 mm / 85.6 in |
| Overall Width | 825 mm / 32.5 in |
| Overall Height | 1300 mm / 51.2 in |
| Seat Height | 998 mm / 39.3 in |
| Wheelbase | 1485 mm / 58.5 in |
| Ground Clearance | 365 mm / 14.3 in |
| Dry Weight | 112.5 kg / 248 lbs |
| Wet Weight | 122 kg / 268 lbs |
| WHEEL SPECS | |
| Front Tyre | 80/100-21 |
| Rear Tyre | 110/100-18 |
| FUEL SYSTEM | |
| Fuel Capacity | 8 Litres / 2.1 US gal |
| Fuel Consumption | — |
| Top Speed | — |
The first 449 cc WR, replacing the WR426F with a larger bore, push-button electric start and a lighter, stronger chassis. Reviewers found its power delivery linear and easier to manage than the 426, making it friendly for trail riders while still enduro-capable.
