From: http://www.mcnews.com.au/
Featuring a fuel-injected engine and improved chassis which should offer the XT buyer more performance than ever before.
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.
In the same way that the new liquid-cooled fuel-injected engine represents a major leap forward in the evolution of the XT series, a new chassis provides more rigidity than before. Whereas previous XT models have featured a single top frame tube, the new XT660R is equipped with dual tank rails that greatly increase overall chassis rigidity. This increased strength allows the XT rider to make full use of the higher power output of the new liquid cooled engine, giving the new XT660R an improved adventure touring function at higher speeds. The 660 cc engine acts as a stressed member.The new frame also incorporates an oil tank behind the head pipe, and the tank’s position at the front of the machine in an area of high air flow makes for excellent heat dissipation to give consistently strong engine performance. Paioli 43mm forks handle the bumps up front and provide 225mm of travel. At the rear of the machine a monocross rear suspension system operates in conjunction with a box section swingarm and rising rate linkage.A large 298mm floating front disc combines with a 245mm rear disc to bring the 165kg machine to a halt. A reasonable touring range should be provided by the 15 litre fuel tank.A new new multi-reflector headlight runs with a powerful 60/55 W bulb for good night time visibility, and a compact windscreen helps deflect wind away from the rider’s upper body for improved comfort. To help protect the machine from theft there is a new immobiliser system built into the main ignition switch. Once the keys are removed by the rider the immobiliser automatically sets itself, making the XT660R virtually impossible to start.The instrumentation on the new XT is all new, and its sophisticated multi-function displays and digital speedometer reflect the greatly enhanced specification of this new generation big single. At the centre of the panel is the LCD speedometer, and next to this are displayed a clock, tripmeter 1, and a multi-function display consisting of a tripmeter 2, odometer and fuel tripmeter. Warning lights display information on engine temperature, engine status, turn signals, fuel level, high beam and neutral, and there is also an indicator light to confirm the status of the XT’s immobiliser system.
Specifications – Yamaha XT660R
- Model - Yamaha XT660R
- Engine - Liquid-cooled, 4-stroke, SOHC, 4 valves
- Displacement - 659 cc
- Bore x Stroke - 100 x 84 mm
- Compression ratio - 10:1
- Max. Power - 35.3 kW (48 HP) @ 6000 rpm
- Max. Torque - 58.4 Nm (5.95 kg-m) @ 5250 rpm
- Lubrication - Dry sump
- Fuel supply - Fuel injection, 44 mm throttle body
- Clutch type - Wet, multiple disc
- Ignition - TCI
- Starting system - Electric
- Transmission - Constant mesh, 5 speed
- Frame - Steel tubular diamond frame with dual tank rails
- Front suspension - Telescopic fork, ø 43 mm
- Rear suspension - Monocross with linkage
- Front wheel travel - 225 mm
- Rear wheel travel - 200 mm
- Caster angle - 28°
- Trail - 118 mm
- Front brake - Single floating disc, ø 298 mm
- Rear brake - Single disc, ø 245 mm
- Tyres - 90/90-21M/C (F) - 130/80-17M/C (R)
- Overall length - 2,240 mm
- Overall width - 850 mm
- Overall height - 1,235 mm
- Seat height - 855 mm
- Wheelbase - 1,500 mm
- Min. ground clearance - 200 mm
- Dry weight - 165 kg
- Fuel tank capacity - 15 litres (reserve 3.5 litres)
- Oil (tank) capacity - 2.9 litres
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