For the 2020 season Yamaha will launch the quicker, stronger and lighter WR250F enduro bike that has been developed from the company’s winning YZ250F motocross machine. Featuring a new high-performance reverse-head engine together with the very latest bilateral aluminum beam frame and state-of-the-art front and rear suspension – as well as slimmer restyled bodywork – the new-generation WR250F is the most advanced 250cc 4-stroke enduro bike ever built by Yamaha.
Throughout its 20-year history this enduro thoroughbred has established something of a reputation for being one of the toughest and most competitive racers at all levels, with numerous national and international victories to its credit. At the same time as being a podium contender in the ultra-competitive E1 class, the WR250F has also become popular with trail riders who appreciate the bike’s ease of use, strong performance and outstanding reliability and durability.
The YZ250F is one of the most competitive motocross bikes at every level – as witnessed by its strong podium performances in the hands of Monster Energy Kemea Yamaha riders Jago Geerts and Ben Watson in the 2019 FIM MX2 World Championship, as well as Dylan Ferrandis’ victory in the 2019 AMA 250 Supercross West Championship in the USA.
The 2020 WR250F engine is closely based on the latest YZ250F design, and features a wide range of performance-boosting technology that gives stronger, linear power throughout the wide operating range. A new forged aluminum piston achieves a higher compression ratio of 13.8:1, and together with optimized exhaust cam timing and new intake port valve seats, these changes boost the engine’s low to mid-rpm torque levels to make this the ultimate E1 enduro weapon.
The previous model’s 10-hole injector is replaced with a new 12-hole injector as well as a new 44mm Mikuni throttle body and a revised intake funnel to give outstanding power characteristics – and to match these changes and improve the power feeling the 2020 WR250F is equipped with a newly designed crankshaft balancer weight. Compared to the previous engine, the 2020 WR250F design delivers stronger power throughout the entire rev range together with increased performance at higher rpm, making it the most competitive 250cc 4-stroke Yamaha enduro bike ever built.
For easy starting with faster restarts during a race the new model is fitted with a lightweight and compact starter motor that’s just 50mm in diameter. Located close to the center of the chassis to achieve an idealized mass centralization, this powerful 390W starter motor is powered by a compact lead type battery, and a new ACM provides a strong and reliable electricity supply. Enduro is probably the toughest environment for any motorcycle clutch. From being slipped mercilessly through technical single-track through to aggressive full-throttle starts on special tests, it has to be able to handle hour after hour of sometimes heavy-handed treatment.
For 2020 the WR250F’s 6-speed wide-ratio transmission features a newly designed clutch that’s both lighter and tougher. Equipped with special heat resistant friction plates with a knurled finish, this new clutch gives a light feel at the lever and is designed to perform consistently and effectively for long periods in the toughest terrain.
Yamaha’s unique reverse head engine features a front facing inlet with the air-box mounted in front of the fuel tank – and for 2020 a newly designed air filter is fitted, enabling tool-free changes. The length of the inlet combined with the special free flow design of the filter contribute towards the new engine’s excellent feelings of traction and linear power, and its welded construction and additional rubber seals around the positioning pin ensure that only clean air reaches the combustion chamber.
