Yamaha 2011—the WR250X

Key Features:

Directly descended from our YZ motocrossers and WR off-road machines—even the original Yamaha YA-1 of 1955—the WR250X is here to make Yamaha’s off-road prowess street accessible. Not exactly an enduro, a supermoto or a sportbike, the WR250X is for riders who ride mostly paved surfaces. Its sibling, the off-road inspired WR250R, is for riders who spend more time in the dirt.

Engine:

250cc liquid-cooled, DOHC engine with two titanium intake valves and two steel exhausts, forged piston and plated cylinder for outstanding durability. Pentroof combustion chamber with downdraft-type straight intake helps make excellent power across the rev band, with maximum power at 10,000 rpm. First use of fuel injection on a 250 Yamaha on/off-road bike. The system relies on input from a crank sensor, intake air pressure sensor and throttle position sensor feeding a compact ECU to provide optimum combustion. An ECU-controlled EXUP® exhaust valve, along with an electronic intake control valve, broadens the powerband. High lift cams have WPC surface treatment in which the surface is sprayed with fine powder at over 100 meters per second to increase surface hardness. Three-axis engine layout keeps the engine compact. Wet sump tucks between frame rails to keep the engine height down. Rare earth-type ACM alternator keeps the weight down while providing all the current needed to run the FI and lighting systems. Direct ignition coil sits atop the spark plug—another first on a Yamaha on-off road model. Six-speed gearbox provides a wide spread of ratios, with shower-type lubrication for reliability. Special, light-action clutch makes shifting a snap. Tucked-in, three-chamber muffler helps keep mass centralized and the bike quiet. Electric start only: Leaving off the kickstarter keeps it light and simple.

Chassis/Suspension:

17-inch wheels mount radial street rubber in 110 front and 140mm rear widths and help lower the seat approximately 1.4 inch compared to the WR250R. One-tooth smaller rear sprocket (13/42) works with the smaller-diameter tires to bring out the WR250X’s strongaccelerating character. Stiffer springs front and rear and street-oriented damping settings reduce pitch compared to the WR250R for excellent pavement performance. YZ/WR250-inspired semi-double-cradle frame uses a main frame of cast and forged aluminum sections, with high-strength steel downtube for excellent strength and rigidity characteristics. Asymmetrical swingarm provides excellent strength/rigidity balance and a dynamic look. Cast aluminum crossmembers, extruded arms and a 22mm rear axle are carefully tuned for optimum handling. Fully adjustable 46mm fork provides 10.6 inches of wheel travel. A forged lower triple clamp and a cast upper one help give outstanding front-end feel. An aluminum steering stem reduces weight. Linkage-mounted rear shock provides 10.4 inches of travel with adjusters for compression damping, rebound damping and spring preload—and features a 14mm rod and 46mm cylinder for excellent damping and fade resistance. Wave brake rotors front and rear, including a large, 298mm front disc, reduce unsprung weight and provide excellent performance. Rear pedal is forged aluminum.

Additional Features:

A slim, steel fuel tank is shaped with knee grip in mind, and the entire ergonomic layout is designed to make the rider feel like part of the bike. Narrow, YZ-inspired seat features gripper-type cover for great seat-of-the-pants feel. Seat height is 35.2 inches. WR enduro-style instrument panel provides excellent visibility in spite of the compact size. Basic mode provides speed, clock, tripmeter and self-diagnostic function. Measurement mode includes stopwatch, distance-compensating tripmeter, etc. Minimalist front and rear fenders are designed for function, simplicity and lightness. Bodywork with separate radiator heat outlet helps keep engine and rider cool. Lightweight headlight and LED taillight maximize visibility and draw less current. Separate clutch cover means easier serviceability. One-screw air filter serviceability. Adjustable front brake lever। /specs Engine Type 250cc liquid-cooled DOHC 4-stroke; 4 valves Bore x Stroke 77.0 x 53.6mm Compression Ratio 11.8:1 Fuel Delivery Fuel injection Ignition Direct ignition coil Transmission Constant-mesh 6-speed; multiplate wet clutch Final Drive Chain Chassis Suspension / Front Inverted fork; fully adjustable, 10.6-in travel Suspension / Rear Single shock; fully adjustable, 10.4-in travel Brakes / Front Hydraulic single-disc brake, 298mm Brakes / Rear Hydraulic single-disc brake, 230mm Tires / Front 110/70-17 Tires / Rear 140/70-17 Dimensions Length 83.1 in Width 31.9 in Height 46.9 in Seat Height 35.2 in Wheelbase 56.1 in Ground Clearance 10.2 in Fuel Capacity 1.9 gal Fuel Economy** 71 mpg Wet Weight*** 302 लब Overall, we came away from our time with the WR more impressed that we thought we might. This slightly-less-than-super supermoto bike gave us more grins than we’d anticipated. As expected, it excels on lower-speed twisty roads, and it does a fine job in a commuter role around town. And, while it’s not an ideal touring mount, it surprised us most by being adequate at highway speeds. It is more than suitable for an hour’s worth of freeway travel while heading for serpentine canyons on which to humiliate larger-displacement sportbikes, piloted by lesser riders. While the WR250X isn’t an ideal choice for a bargain hunter who is shopping for an inexpensive commuter bike, it has plenty of high-end details and useful features baked into it that add up to a unique sporting machine a gearhead can be proud of. We liked it so much that we’re not yet ready to give it back. So we’re fitting some Yamaha accessories to it while we wait for a Kawi KLX250SF test mule. Is the more powerful WR $900 better than the new KLX-SF? And, if we’re lucky, we might toss in the DR-Z400SM to see which Japanese manufacturer has the best overall supermoto package for the dollar. This is gonna be fun! The WR gets kudos for its light weight (299 lbs ready to ride with a tank of fuel) and for its nimbleness, but short people will wish for a seat height lower than the WR’s 35.2 inches. Steering effort (if you can call it that) is incredibly light thanks to a wide motocross-style handlebar, and its super-tight turning radius makes it easy to maneuver in the garage and when filtering through traffic. However, clutch engagement a bit lurchy and inconsistent, while the gearbox is occasionally notchy. No worries about this little ripper of a motor. The 250cc liquid-cooled, DOHC engine with two titanium intake valves and two steel exhausts features a fuel-injection system that takes input from a crank sensor, intake air pressure sensor and throttle position sensor. The compact ECU also controls an EXUP exhaust valve to broaden the powerband. Valve-adjustment intervals are a lengthy 26,000 miles. Specifications .: Engine Engine type Liquid cooled, 4-stroke, DOHC, 4-valve, forward inclined single cylinder Displacement 250 cc Bore x stroke 77.0 X 53.6 mm Compression ratio 11.8:1 Maximum power 22.6 kW (30.7 PS) @ 10,000 rpm Maximum torque 23.7 Nm (2.42 kg-m) @ 8,000 rpm Lubrication system Wet sump Fuel System Electronic fuel injection Clutch type Wet, multiple-disc coil spring Ignition system TCI Starter system Electric Transmission system Constant mesh, 6-speed Final transmission Chain Fuel tank capacity 7.6 L Oil tank capacity 1.5 L

Related Posts

Baca Juga