The Yamaha WR450F is completely new for 2019. It features an all-new engine, updated suspension settings, and a reworked chassis. Yamaha’s flagship enduro bike is based on the YZ450F platform but features several differences to make it more suitable for trail riding.
The WR450F engine is based on the current YZ450F with specific enduro settings. The intake, exhaust system, and EFI mapping are all tuned to provide stronger and longer-lasting pulling power at high rpm. The trailbike has a new air filter, an intake funnel that has a different length than the previous year, and a model-specific sound-damping muffler design.
The WR450F also shares engine components with the all-new 2019 YZ450FX. The wide-ratio five-speed transmission has the same spec and gear ratios as the cross-country machine, and the shape of the dog gears have been revised. The clutch design is also similar, which eliminates the need for a judder spring, and it uses the same friction plate.
The electric starter motor has been repositioned from the front of the engine to just behind the cylinder, contributing to mass centralization. According to Yamaha, this reduces drag and horsepower loss—a 60-percent reduction in load compared to the previous model. The kickstarter has also been eliminated to save weight.
The WR450F uses the same KYB Speed Sensitive System (SSS) coil-spring fork as the YZ450F, but with model-specific enduro settings. The diameter of the cartridge cylinder and piston have been increased compared to the prior generation model going from 24mm to 25mm. The Mid-Speed Valve (MSV), which provides damping in the mid-speed range, has been changed from a coil-spring type to a leaf-spring type.
The shock is similar to the one found on the YZ450F but features enduro-model-specific settings. It has a coil spring with a higher fatigue strength than the previous model. By using an 11.5mm wire diameter on the shock spring, Yamaha was able to reduce the weight of it by approximately 350 grams (12.3 ounces). The capacity of the shock reservoir has been increased by 30cc in an effort to help it run cooler and achieve a more stable damping force.
Another component on the WR450F that is similar to the YZ450F is the frame. However, the WR450F uses different front engine-mount brackets to fine-tune the rigidity. The chassis is also more compact from front to rear. The radiator shrouds have a new air duct with a concave shape that is narrower and improves styling. The seat height has been reduced and the handlebar is now four-way adjustable too.
The WR450F has a new 2.2-gallon fuel tank that is 0.5-gallon larger than the previous model. Attached to the larger plastic resin tank is a new fuel pump. It also has a new headlight cowl, a different lightweight front wheel speed sensor, an updated skid plate, and a lighter kickstand. The 2019 WR450F will be available at Yamaha dealerships beginning January 2019 for $9,599.