The new WR250F engine is based closely on the winning fuel-injected YZ250F design, and features a rearward-inclined cylinder and reverse cylinder head. Its airbox is situated in front of the rider and the fuel tank located at the centre of the bike – a unique configuration that contributes to the bike’s mass centralisation, which plays a pivotal role in achieving light and agile handling.
In addition, the WR250F’s reverse cylinder head allows the use of a straight air inlet for higher levels of intake efficiency, and by locating the fuel tank centrally, this innovative design permits the use of a long and flat seat that allows the rider to shift their body weight quickly and easily.
The 2020 WR250F features a new high compression forged aluminium piston, revised valve angle and exhaust cam timing with revised balance factor – all based on the current YZ250F, but with enduro specific settings to provide a high level of winning performance. That performance is further boosted by the fitment of a dual electrode spark plug and revised exhaust muffler for 2020.
Compared to the former WR250F engine, the 2020 design is more powerful at higher rpm, and also delivers stronger power right through the rev range, making it a serious contender for top honours.
Free flow air filter contributes to linear response
The filter element features reduced airflow resistance and intake noise combined with increased reliability. The new filter and the length of the intake funnel contribute to an excellent feeling of traction and linear characteristics during acceleration and deceleration. Plus, dust filtering capability is increased by adding rubber seals to the centre positioning pin.
Lighter, tougher clutch
The 2020 WR250F is equipped with a 6-speed transmission that is designed to handle a wide variety of terrain, from technical rock climbs to full throttle blasting along forest tracks. A new lighter and tougher clutch is now mated to the box to match the extreme demands of enduro riding. Featuring new heat resistant friction plates, this durable clutch has a super light lever pull and is built to perform consistently and effectively for long periods in the toughest terrain.
Mass centralised starter system
A lightweight starter motor contributes to mass centralisation. Also, a garter spring is adopted for the spring of the one-way starter clutch in order to reduce horsepower loss – a 60% reduction in load compared to the outgoing model.
New smartphone tuning
On board WiFi means that you can tune the new WR250F to different track conditions using your smartphone. A downloadable Power Tuner app allows you to make fuelling and ignition timing changes instantly and upload/share them for the ultimate in track-side tuning. The free Yamaha Power Tuner app also allows owners to record ride/race log information and monitor a range of data such as maintenance and system diagnosis, engine run time and more.
The on board WiFi is available thanks to a Command Control Unit (CCU) that contacts the ECU and forms part of the free competition kit offered to Australian customers.
Engine map switch
A bar-mounted dual engine map switch has been adopted and positioned next to the left lever to enable changes in the engine power delivery characteristics mid-race. This switch allows the rider to select one of two engine maps on the fly at the press of a button to cater for changes in the riding environment.
This means that when the going gets loose, steep or muddy – high traction can be accessed at the press of a button.
YZ250F bilateral beam frame
WR250F now runs the same bilateral beam frame as the sharp handling current model YZ250F. To achieve a rigidity balance with the amount of flex needed for enduro riding, the engine mount brackets have been altered. The upper-side mounts are the same as on the YZ250F, while two-plate type mounts are used for the front-side mounts.
The result contributes to the machine’s excellent feeling of contact with the ground and offers feedback about the riding surface while providing a light feel to the handling.
WR250F runs the same KYB air-oil-separate closed chamber upside-down front fork as the YZ250F but with model-specific enduro settings to provide stable damping force. This suspension is acknowledged to be the best available on a production dirt bike and responds particularly well during the transition between the compression and rebound strokes. And because the suspension holds up well in the stroke, ground clearance is improved over the outgoing model.
The outer tubes are the same as the YZ250F and contribute to a secure feeling of ground contact. The mid-speed valve (MSV) that provides damping in the mid-speed range has been changed from a coil spring type to a leaf spring type. This mechanism responds to even the slightest amounts of oil flow and so delivers excellent damping feel at low speeds.
The rear shock absorber is also based on the YZ250F unit and features enduro model-specific settings. It features a coil with a higher fatigue strength than the current model’s and with an 11.5mm wire diameter achieves a weight reduction of approximately 350 grams. The capacity of the reservoir has been increased by 30cc to run cooler and achieve a more stable damping force.
More protective bashplate
The new WR250F features a more protective plastic resin engine guard to help prevent damage to the frame, engine, water pump and hoses when running through ruts or from impacts by kicked up rocks. Also, reducing the size of the open space at the front limits the amount of mud and stones entering and so reduces additional running weight.
Larger fuel tank
A newly designed 7.9-litre plastic resin fuel tank is featured that reduces the frequency of refuelling during longer distances. The current YZ250F’s tank was used as the developmental base, and the lower portion has been extended toward the centre of the bike to improve mass centralisation, and to increase the tank’s capacity.
A compact fuel pump is another new feature. These changes have made it possible to achieve a slim, compact body design comparable to the YZ250F that also results in minimum interference with the riding position.
Flatter, lower seat
A redesigned seat with stiffer seat foam is fitted to aid rider manoeuvrability and to make getting on and off the bike easier. A slimmer design through the shroud/knee contact area helps further improves rider ergos.
New forged aluminium sidestand
A lighter and less obtrusive forged aluminium sidestand is positioned to ensure plenty of ground clearance when riding through ruts and the like. The new stand sits higher and the amount it juts out from the chassis is reduced which helps prevent snagging. The weight of the stand has also been reduced by about 100g. This is the same as the 2019 model YZ250FX stand design.
Sleek new headlight cowl
The WR250F’s new headlight cowl sits lower and closer to the rider. It contributes to centralisation of machine mass and helps to create a light, agile impression for the machine.
Lightweight speed sensor with high-precision display
A new lightweight front wheel speed sensor connects to a highly precise speed display and with no more speedo drive, makes front wheel changes easier. The system features a pulse wheel and sensor system known for excellent reliability and provides the detailed speed information essential for enduro riding. Display includes low fuel warning light
18-inch rear wheel and high grip tyres
The WR250F runs with an 18-inch rear wheel, allowing for a wide range of tyre fitment. Standard high traction Metzeler 6 Days Extreme enduro pattern front and rear tyres are specced, making this new bike ready to race straight from the showroom.
Off road competition kit
For the Australian market, the new WR250F is supplied fully ADR compliant and in road registerable condition. A free competition kit is supplied and can be easily fitted for closed course use. The kit includes:
• CCU for smartphone tuning capability
• Lightweight LED tail light/ and licence plate holder
• Competition larger diameter exhaust muffler outlet
• Full power / full travel throttle stopper screw kit
• YZ airfilter holder guide
• Wiring connector for headlight
• Brake snake kit
• Wiring connector for rear brake light
• WRF Barkbuster handguard set