The Yamaha WR450F 2-Trac is a rally bike, a limited production competition machine featuring the world’s first production two wheel drive system for motorcycles.
Based closely on the successful WR450F four stroke Enduro machine, the WR450F 2-Trac is the result of many years of joined development by Yamaha and Öhlins Racing AB.
The patented 2-Trac system uses a hydraulic pump situated on top of the gearbox, and a chain running in an oil bath drives the mechanism. The system pumps hydraulic fluid via high-pressure hoses to the front wheel hub which is fitted with a hydraulic motor equipped with a single gear. When the fluid has passed through the motor it passes through a filter and returns to the pump.
2-Trac is a ‘smart’ self-regulating system. Hydraulic pressure to the front wheel increases as the rear wheel loses traction on loose surfaces, and so the amount of power being transmitted to the front wheel is constantly changing so that the best ratio is always being applied. The front wheel can never spin faster than the rear wheel, and the amount of power transmitted to the front wheel is never greater than the wheel can use for traction. This self-regulating system also ensures that the hydraulic power supply to the front wheel is reduced as soon as the rear wheel regains full traction.
The new Yamaha WR450F 2-Trac rally machine will be produced in a limited series for competition use only, but the actual 2-Trac system clearly has the potential to be used in a range of motorcycle and scooter applications in the future. For different MC and SC concepts, 2-Trac has enormous potential both as a means of effectively handling the increasing power output of larger machines, yet also as an anti-spin device.
Following future market research results and potential customer demand, Yamaha will further study the adaptation of 2-Trac in other products. In addition to the new WR450F 2-Trac rally version, Yamaha is currently studying the possibilities of a YZ450F 2-Trac Supermoto.
- Engine type: 4-stroke, DOHC, 5 titanium valves
- Engine cooling: Liquid cooled
- Displacement: 449cc
- Bore x stroke: 95 x 63.4mm
- Compression ratio: 12.5:1
- Lubrication system: Dry sump
- Carburettor: Keihin FCR39H
- Clutch type: Wet, multiple-disc
- Ignition system: CDI
- Starter system: Kick and electric
- Transmission system: Constant mesh, 5-speed
- Final transmission: Front wheel: hydraulic / Rear wheel: chain
- Fuel tank capacity: 10 litres
- Oil tank capacity: 1.7 litre
- Front suspension system: öhlins Upside-down telescopic fork
- Front travel: 300mm
- Rear suspension system: öhlins shock absorber, Link-type suspension
- Rear travel: 315mm
- Front brake: Single disc, Ø 250mm
- Rear brake: Single disc, Ø 245mm
- Front tyre: 90/90-21
- Rear tyre: 130/90-18
- Length (mm): 2,171mm
- Width (mm): 827mm
- Height (mm): 1,303mm
- Seat height (mm): 998mm
- Wheel base (mm): 1485mm
- Minimum ground clearance (mm): 371mm
- Dry weight (kg) 119.5 kg