Already renowned for its enormous power output, the WR450F engine has been thoroughly redesigned to deliver stronger and more controllable performance. The engine is essentially the new generation YZ450F tuned with enduro settings - which means its significantly more compact and lighter than the previous generation engine. The revised configuration enhances the bike's mass centralised design to make it one of the easiest-handling large capacity enduro machines. Featuring increased compression ratio – up from 12.8:1 to 13:1 – the reverse cylinder head also runs a durable forged piston and aggressive cam profiles. New intake/exhaust systems and ECU run WRF specific settings to deliver the best balance of race-winning performance together with ultimate controllability for tight trails.

The cylinder head weighs 310g less and is significantly more compact than previous generations. Because this innovative design is positioned close to the bike's mid-section it helps to achieve an idealised mass centralisation, and this contributes enormously towards the WR450F's dynamic handling characteristics. The intake/exhaust valve angles and intake port design are changed and a new piston with a small recess is specified to create a more concave combustion chamber for increased power. This new high-efficiency head with its long and straight inlet, produces a fine balance of power with exceptional controllability.

In 2019 the WR450F became the first enduro bike with inbuilt connectivity featuring remote wireless tuning using a smartphone. Now the 2021 model continues to lead the field in digital technology. By downloading the free Power Tuner app for IOS or Android devices, WR450F riders can easily adjust the fuel/air mix and ignition timing to set the bike up for different riding conditions. This feature makes the 2021 WR450F the most adaptable enduro machine – and one that can be tuned instantly on the trail, allowing riders to make the most of a wide range of surfaces and weather conditions. In addition to its engine re-mapping function, the Power Tuner app can also record information and monitor a range of data, including system diagnosis, engine run time and more, making it an indispensable part of every rider's toolkit.

The WR450F features a handlebar-mounted mapping switch (blue button) that enables the rider to select one of two power maps on the fly. This simple adjustment allows instant engine delivery changes to suit variable terrain or weather conditions. For example, from an aggressive map for fast dry conditions to a high traction map for slippery hillclimbs.

The new 450 engine is equipped with a compact and lightweight electric starter that gives push-button convenience for hassle-free starts – especially useful on the side of a hill.

The compact new engine is equipped with a highly advanced Mikuni fuel injection system that features a light and ultra-compact 44mm throttle body. Delivering the fuel/air mix via a long and straight forward facing inlet, this advanced fuel injection system benefits from a high pressure electric pump that ensures optimum atomisation for excellent running performance in a wide range of riding conditions.

To ensure that the new more powerful engine runs efficiently in all conditions, Yamaha's engineers have developed radiators that are angled to directly face the incoming air. By maintaining a consistent airflow, this angled radiator layout delivers effective engine cooling for winning performance. A thermo fan cuts in to keep the fluid cool when the going gets tough.

The WR450F's robust 5-speed transmission is built to handle even the most aggressive left foot. The specially-developed gears feature a large surface area that spread the load, and third and fourth have received a surface treatment to increase durability. In addition, the shift drum and selectors now give improved feel and a shorter stroke when shifting gear. Ratios are ideal for enduro riding with lower gearing from first to third gear and taller-geared fifth compared to YZ450F.

A key feature of the WR450F is its mass centralised design, in which major components are located as close to the bike's centre of gravity as possible. One example of this is the wraparound exhaust that snakes around the cylinder - this design also enables the fitment of a muffler that is mounted close to the bike's centre. For 2021 the WR450F runs a YZ450F exhaust with WRF specific muffler to achieve the goal of increased power with control. Combined with the rearward-slanted cylinder, the exhaust centralises mass and contributes significantly towards lightweight and dynamic handling performance.

For 2021 the WR450F uses the same bilateral beam frame created with controlled fill technology as the flagship YZ450F motocross bikes. But the chassis is tuned for enduro use with WR specific engine mount brackets. Our designers carefully retuned the compact YZ aluminium frame to match the more powerful engine. To reduce weight and fine tune the bike's instinctive handling performance, the new bilateral frame features thinner main spars together with thicker bottom tubes. In order to achieve the balance of rigidity and flex for enduro riding, the shape and bolt tightening settings of the front and rear engine mount brackets have been revised. The combination of these measures offers an improved feeling of connectivity to the ground, clear feedback from the riding surface when going over bumps and light handling.

In order to improve the front end feeling, the rigidity balance has been revised on the top triple clamp, front wheel axle and bar mounts. These items have been redesigned to be lighter yet stronger to offer a better front end feel – and the bars are moved 15mm further forward and 5mm lower to help the rider get over the front end in order to improve grip and steering.

The WR450F is equipped with fully adjustable coil spring twin chamber KYB® forks from the YZ450F that are widely regarded as being the ultimate in off-road suspension. Featuring enduro settings and speed sensitive damping that gives the idealised balance between handling and bump absorption, these exceptional front forks deliver best-in-class performance. The fully-adjustable link-type rear end settings are aslo revised to match the new frame and front end. The setup features a specially tuned KYB® shock absorber that delivers high levels of traction together with smooth suspension action at low and high speeds, giving exceptional handling in a range of track conditions.

Braking performance has been improved by running the 2020 YZ450F setup. This gives the brakes strong braking force and controllability in response to rider input. Compared to the 2020 WR450F, the caliper pistons have been made larger - 22.65 mm to 25.4 mm - while revisions to the caliper body increase rigidity by 30 per cent. New brake pads generating consistent friction were incorporated and the brake pad surface area increased by 25 per cent. Changes in the shape of the front rotor stay have increased the pad contact surface area by 16 per cent without any increases in weight.

A slimmer and more compact multifunction display is specified for the 2021 WR450F. The display features an odometer, two tripmeters, a clock, timer/stopwatch and a new and very useful fuel consumption indicator. Low fuel and engine warning lights also feature. On the 2020 model, the instrument cluster and warning lights were separate but the 2021 model now has the warning lamps built into the display. This increases their visibility and makes for a neater area around the instruments. The layout of the display has also been redesigned, with a higher-contrast liquid crystal display and white background ensuring improved readability.

Footpeg weight has been reduced by approximately 70g by changing from stainless steel to the chromoly steel pegs also specced on the 2020 YZ450F.