Yahama WR250R/X Release April 2008

This has been achieved by designing the bike to combine first rate performance both on the dirt and the tar in a setup that doesn't require the same high service requirements demanded by full enduro race spec motorcycles. Both motorcycles come with long service intervals and a two year warranty. The WR250R (and WR250X Supermoto version) are powered by a new fuel injected 250cc engine that meets the strictest emission laws slotted into a neat hybrid steel/aluminium chassis that is equally capable on the road or in the bush. The liquid-cooled 4-stroke DOHC 4-valve engine has been built to deliver outstanding acceleration and instant response that exceeds anything ever offered in the 250cc single cylinder street legal category. It features the same big 77.0mm bore and short 53.6mm stroke as Yamaha's Grand Prix winning YZ250F motocrosser and WR250F enduro bikes.

The all new short stroke engine features a specially designed 4- valve cylinder head with a compact pent-roof combustion chamber which helps the WR250R deliver instant throttle response and strong performance right through the rev range to its maximum power output at 10,000 rpm. The new cylinder head features a high 11.8:1 compression ratio, and utilises extra large titanium intake valves. The new WR250R is equipped with a fuel injection system - the first time this has been used on a Yamaha 250cc on-off road bike. The compact ECU unit receives data from a crank sensor, intake air pressure sensor and throttle position sensor, allowing it to calculate fuel injection, giving crisp throttle response, fuel efficiency and clean running.

Overall intake efficiency is greatly enhanced by the use of a new downdraft-type straight intake system. The use of this intake has been made possible by the adoption of a newly designed rear suspension linkage which frees up space behind the engine. The intake is equipped with an air control valve, which, together with the EXUP system fitted to the exhaust, allows the ECU to accurately control the WR250R engine's airflow from the intake through to the exhaust. Highly efficient heat dissipation is one of the key factors that allow the new WR250R to deliver consistently strong performance at high rpm.

A lightweight heat-resistant forged piston runs in the plated cylinder. This combination ensures that the engine is able to deliver a consistently strong supply of power. In addition, the single radiator is equipped with a high efficiency blower which maintains the system's cooling function at lower speeds, and in doing so helps to achieve optimum power and reduced oil consumption. The new WR250R benefits from a wet sump lubrication system which offers a number of advantages. Because this system contains all the lubricating oil in an oil pan beneath the engine, there is no need for an external oil tank or reservoir, and therefore no external oil pipes are required.

The wet sump design also requires fewer parts and is lighter, while the absence of external oil pipes also enhances the overall aesthetics of the engine. More on the WR 250R/X on the following page. The efficient design of the WR250R's chassis has allowed the wet sump to be accommodated between the tubes of the double cradle frame, thereby keeping engine height to a minimum, which allows for a generous 300mm of ground clearance. Direct ignition coils are featured on the WR250R - the first time this advanced system has ever appeared on a Yamaha on-off road bike. This system incorporates a booster in the spark plug cap, eliminating the need for a frame mounted ignition coil - as well as reducing weight and freeing up space above the engine.

The WR250R/X features the first 3- section semi-double cradle frame ever used on a Yamaha on-off road model. This advanced new semi-double cradle frame has been developed using technology from the race winning YZ250F motocross bike and the WR250F enduro machine, and consists of a cast aluminium/ forged aluminium main frame, steel down tube and steel subframe. The main frame features cast aluminium components for the front and rear sections, with forged aluminium parts for the rest, and these are welded together to create an extremely light and enormously strong unit. Manufactured from thin walled 25.4mm diameter steel pipe, the high tensile single down tube offers a number of advantages over conventional designs.

Firstly, being a separate component, it facilitates engine mounting during manufacture. Secondly, the design helps achieve the desired ground clearance with the new wet sump engine. Virtually every aspect of the WR250R has been designed and manufactured to an advanced competition-type specification, and this commitment to high quality components can also be seen in the new aluminium swinging arm. Like the main frame, the innovative new swinging arm utilises a special combination of aluminium components in order to achieve the desired balance of strength and rigidity, and its low unsprung weight also ensures improved rear suspension performance.

To complement the advanced new 3-section frame, the WR250R is equipped with a high-spec suspension package which has been designed to be able to handle a diverse range of on and off road riding conditions. At the front end the WR250R is fitted with race quality upside-down front forks with 270mm of travel, equipped with flex resistant 46mm tubes which deliver a good balance of rigidity. Like Yamaha's motocross and enduro bikes, the WR250R's forks feature lightweight aluminium triple clamps - cast aluminium for the handlebar crown and forged aluminium for the under bracket.

Aluminium is also used for the steering shaft in order to minimise weight for responsive steering. The WR250R's instrumentation has been designed to offer good levels of visibility and operability, while also being light and compact. The basic mode display includes a speedometer, clock and trip meter, while the measurement mode includes a stopwatch and distance compensation tripmeter. Yamaha's designers have concentrated their efforts on ensuring that weight is kept as low as possible, and that there is also a good concentration of mass.

This has been achieved by using lightweight and compact components wherever possible - such as the rare earth AC magneto and direct ignition coil. In addition, the new muffler has been positioned close to the machine's centre of gravity, and the size and weight of the front and rear fenders and sidecovers has been minimised to help concentrate the machine's mass. The handlebar/seat/footrest relationship has been carefully chosen in order to create a comfortable yet effective, upright riding position which makes the rider feel at one with the machine. The slim steel fuel tank offers excellent knee grip, and the frosted finish competition style seat allows easy weight shifting when riding off road. And with its 930mm seat height and 300mm ground clearance, the exciting new WR250R is ideally suited to challenging off road conditions.

WR250R/X SPECIFICATIONS
EngineEngine type: Liquid cooled, 4-stroke, DOHC, 4-valve, forward inclined single cylinder
Displacement: 250 ccBore x stroke: 77.0 X 53.6 mm
Compression ratio: 11.8:1Lubrication: Wet sump
Fuel System: Electronic fuel injection
Clutch type: Wet, multiple-disc coil spring
Ignition system: TCI
Starter system: Electric
Transmission: Constant mesh, 6-speed
Final transmission: Chain
Fuel tank capacity: 7.6 L
Oil tank capacity: 1.5 L
Chassis: Semi double cradle
Front suspension: Telescopic forks
Front travel: 270 mm
Rear suspension: Swingarm (link suspension)
Rear travel: 270mm
Front brake: Single disc, Ø 250mm / Ø 298mm
Rear brake: Single disc, Ø 230mm
Front tyre: 80/100-21M/C 51P/ 110/70R 17M/C 54H
Rear tyre: 120/80-18M/C 62P/ 140/70R 17M/C 66H

Dimensions
Length: 2180mm /2115mm
Width: 810mmHeight: 1230mm /1190mm
Seat height: 930mm /895mm
Wheel base: 1420mm /1425mm
Min ground clearance: 300mm / 265mm
Dry weight: 126kg /128kgRRP: $9999/$10,399
Warranty: 24 months, unlimited kms, parts and labour
Colours: Racing Blue or Sports White/ Sports White or Yamaha Black

WR250X FEATURES
-Featuring the same advanced technology as the WR250R, the all new WR250X has been developed to offer quick changes of direction, high levels of traction during cornering, great stopping power and a lower seat height for good control in urban situations.
-The supermoto-style WR250X runs with 17-inch front and rear wheels equipped with a 110mm wide front tyre and 140mm wide rear tyre featuring a radial construction.
-The radial tyres deliver lower rolling resistance and high levels of traction for remarkable road holding qualities, making the WR250X an agile and responsive machine in the urban environment.
-To accommodate the different size and handling characteristics of the wide radial tyres, the WR250X runs with revised suspension settings at the front and rear.
-The WR250X front forks utilise stiffer springs and run with different damping settings in response to the pure street usage of the machine - as well as to handle the increased braking power of the new front disc.
-Meanwhile the rear suspension has also been modified with revised damping settings and a stiffer spring - and in order to achieve a 35mm reduction in seat height for improved controllability, the WR250X features a slightly shorter rear shock absorber.
-These changes to the suspension perfectly complement the handling characteristics of the new radial tyres and 17-inch wheels to create a sharp handling machine which offers new levels of cornering potential, together with remarkable overall agility and directional changes.