Motorcycle specifications YamahaWR 250 F 2015 The YZ invites itself to enduro racing

yamaha unveils an all-new WR 250 F for 2015: the first enduro bike equipped with Yamaha's famous rear-tilted cylinder and inverted cylinder head engine.

developed from the 2014 YZ 250 F, winner of the AMA MX250 motocross championship, the new WR 250 F has the potential to win the toughest competitions.

the new engine of the WR 250 F is closely derived from the fuel-injected engine of the YZ 250 F, which has enjoyed such recent success. For the first time in the enduro world, the engine features a rearward-tilted cylinder and an inverted cylinder head. The airbox is located in front of the rider, and the fuel tank in the middle of the bike. This unique layout contributes to the centering of mass, a key factor in lively, agile handling.

the new WR 250 F retains the same bore and stroke dimensions, compression ratio, cam profile, forged aluminum piston and case-hardened crankshaft as the YZ 250 F. Compared with the previous WR 250 F engine, the 2015 version is considerably more powerful at high revs, and also offers a stronger feeling of power throughout the rev range.

in addition to its new long 6-speed transmission, the WR 250 F is equipped with a special enduro clutch whose characteristics enable it to meet extreme demands.

made entirely of aluminum, the WR 250 F's double-beam frame is closely derived from that of the YZ 250 F.

one of the outstanding features of the YZ 250 F is its front suspension system. The separation of the air and oil chambers is the main reason behind the success of this high-tech inverted fork.
This idea of separate air and oil chambers reduces aeration and cavitation over bumps, offering more stable damping. This cutting-edge system is used on the 2015 WR 250 F model with specific settings for enduro use.

the new WR 250 F benefits from the same rear shock absorber as the YZ 250 F. To meet the diverse requirements of enduro riding, the shock absorber's length, spring rate and stroke have been optimized. Compared to the YZ 250 F, the WR-F has a 4 mm longer shock absorber, which increases rear travel by 10 mm.

wR 250 F technical specifications

engine

- Based on the 2014 YZ 250 F model
- Rear-tilted fuel-injected engine
- Inverted cylinder head with direct front intake
- snake exhaust for improved mass centering
- New injection settings
- Engine tuning via Yamaha Power Tuner
- Long 6-speed gearbox with enduro clutch
- New electric starter with switchless system
- 1,100 cm³ engine oil capacity, 200 cm³ more than YZ 250 F model
- WR450F alternator and MF battery
- Top-mounted air filter with quick-release fasteners
- Redesigned decompressor
- New crankcases

frame

- Compact aluminum chassis with short rear loop
- Double-sided aluminum frame
- Centered 7.5-liter fuel tank
- New suspension settings for enduro use
- YZ-F-type front fork with separate air/oil system
- 10 mm more rear travel than YZ 250 F
- 18-inch rear wheel
- Metzeler 6 Days Extreme FIM tires
- Lightweight side stand
- WR450F-type front and rear lights
- Radiator with new electric fan
- Crankcase guard
- Speedometer, fuel level and engine warning lights
- New exhaust silencer
- Long, flat seat with concealed fuel filler cap
- New plastic trim

Photo credits: Yamaha France