Yamaha XT660R (2004)

Yamaha’s XT600 has been a long time trusted mount but has been long overdue for an update.

Now, three decades on from the launch of the original ground-breaking XT500, the legendary XT brand is reborn in the shape of the new XT660R.

Featuring a fuel-injected engine and improved chassis which should offer the XT buyer more performance than ever before.

Yamaha launched the original XT500 in 1976, and the new model was the first four-stroke single ever produced by Yamaha. The XT500 was also one of Yamaha's longest running production models, running through to 1989. In 1982 Yamaha also launched the XT550 with a new chassis and monocross rear suspension. 1983 brought the XT600Z Tenere with a large fuel tank and other changes which resembled the factory Paris-Dakar machines of the era.

Introduced in the late 1980s, the XT600 was quick to establish itself as one of Yamaha’s most popular middleweights, and during the 1990s the model underwent a number of technical and stylistic changes, culminating in the XT600E that came to the end of its long and successful production run in 2003.

The new XT660R is clearly aimed at riders who need a machine that can handle everything from poorly surfaced rural roads and trails through to urban streets and flowing open roads. Yamaha are also targeting urban based riders who use their machine for daily commuting as well as leisure riding out of town.

The new XT is powered by an all-new fuel-injected single cylinder engine that has been designed to deliver strong torque in the low and middle rpm ranges. The new motor is the most advanced large capacity single ever produced by Yamaha and is a long way ahead of the air-cooled XT600 engine it replaces.

Fuel injection is added to a single for the first time by Yamaha in the new machine with a single 44mm throttle body combining with a specially long 12-hole injector for optimum fuel efficiency.

Complementing the XT’s fuel injection system is a newly designed cylinder head that offers higher levels of intake and exhaust gas flow efficiency. The new SOHC 4-valve head runs with large diameter 38 mm intake valves and 32 mm diameter exhaust valves.

The new machine is fitted with an automatic decompressor which is similar in design to that seen on the YZ and WR competition four-stroke models.

The new aluminium cylinder runs with a 100 mm bore and 84 mm stroke, and features a ceramic composite plated bore that offers improved heat dissipation and helps reduce weight. Running in the low-friction plated cylinder is a lightweight forged piston which squishes a 10:1 compression ratio. Spent gases are expelled through twin header pipes before terminating in to a pair of high-rise silencers.

Helping the rider to make the most of the engine is a new five-speed gearbox which is significantly stronger than that seen on previous XT models. All gears from second through to fifth feature five gear wheel dogs (compared to three on previous Yamaha models), whilst first gear runs with four dogs. In addition to the uprated gears, three shift fork bars (instead of two) are featured, whilst the shift cam segment shape has been optimised, and finally the XT660R’s shift shaft runs on two bearings.