Motorcycle specifications YamahaWR-F 450 2-TRAC 2004 It pushes and pulls!

although the idea is not new, this is the first motorcycle to be marketed with 2-wheel drive. We dreamed of it - Yamaha and Öhlins made it happen. To showcase the qualities of this system, Yam has chosen a machine full of bravura that can just as easily venture into the sandy dunes of the desert as into the undergrowth of a Vendée forest. This machine is particularly well known in today's African rally competitions. And at first glance, the system is very discreet and remarkably well integrated. What's different from the standard 450 WR-F? Visually: a larger hub in the front wheel, 2 hoses and a housing at the pinion output. That's it... and the whole thing is surprisingly compact. Because 2-wheel drive requires quite a gas factory. So, how does the 2-TRAC work...? In simple terms, the housing next to the engine is an oil pump driven by a whole mess of gearbox output. The pressurized fluid passes through hoses that run up to the handlebars and along the fork to the hub. The pressurized oil in turn drives a motor in the hub, which transmits up to 30% of the power to the front wheel. Simple, isn't it?

the 2-TRAC only works when the rear wheel starts to spin. It then distributes part of the power to the front wheel. Certain peripheral devices have to adapt as dynamic constraints also change. New fork, special rear shock absorber and steering damper. On the handlebars, the differences are really noticeable compared to the standard WR-F. Traction in tricky spots is much better, steering control is easier on rough roads, and gliding trajectories on "hard" terrain are better controlled. There's a definite feeling of safety, as the bike seems to help you exercise. As a result of its drive function, the front wheel tends to harden the fork a little when towing; not really a nuisance, as the efficiency of the 2-trac quickly erases this minor inconvenience psychologically. A real advantage whose use will certainly not be limited to the cross-country world.

M.B
(inspired by M. Montange's article - Moto-journal n° 1 593
manufacturer's photos)