Yamaha Offers Two-Wheel-Drive
September 10, 2004
Filed under Features
Yamaha’s WR450F 2-Trac rally bike, a competition machine featuring the world’s first production two-wheel-drive system for motorcycles, is now available. So far, the only problem is that it’s not available in the U.S. For now, qualified competition riders will have to go seek one of the limited production units in France.
Based closely on the successful WR450F four-stroke enduro machine, the WR450F 2-Trac is the result of years of joined development by Yamaha and Öhlins Racing AB.
Research was initiated in 1985, and the two companies tested and evaluated a wide range of mechanical and hydraulic drive systems on a number of different two-wheelers, including a YZ250, a TT600R, a WR426F, and even a YZF-R1.
There are two systems available for powering the front wheel of a motorcycle – mechanical and hydraulic. The patented 2-Trac system uses a hydraulic pump situated on top of the gearbox, and the mechanism is driven by a chain running in an oil bath. 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, supplying up to 15% of the engine power to the front wheel in a constantly changing ratio.
Yamaha says further market research is needed before it decides to adapt 2-Trac to other products. Still, company officials say they believe that the system can be adapted to suit virtually any standard production motorcycle without requiring major changes to the engine or chassis, and so represents the future for two-wheel-drive motorcycles. psb