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All parts of the CRF450R are new for 2021, with the exception of the wheels and engine. The comprehensive update benefits directly from the know-how that HRC was able to collect through the development of Tim Gajser’s HRC machine, with which he rode to the world championship title in 2019. The new frame and the new swing arm as well as changes to the geometry and suspension save weight and significantly improve cornering behaviour. The engine receives improvements to the intake system and exhaust, a new decompression system and a single muffler – all of which together result in a softer response and improved driveability in the lower and medium engine speed range. A larger hydraulic clutch provides more control with less leverage. More compact plastic parts and a smaller seat increase freedom of movement.

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The 2021 model of the CRF450R has a wide range of improvements and upgrades, all of which can be summarized under the development theme “razor-sharp steering”. First, the machine is 2 kg lighter thanks to a revised frame and subframe. In addition, the rigidity balance of the new frame and the swing arm in conjunction with a tighter chassis geometry, greater ground clearance and changes to the suspension are all geared towards optimal cornering behaviour. The knowledge gained from Tim Gajser’s 2019 World Champion season reduces driver fatigue and enables enthusiasts of all performance classes to achieve consistently optimal lap times.

The engine also benefits from HRC’s know-how: it now places a strong focus on torque in the low to medium speed range. The decompression unit was relocated, the volume of the airbox increased, the throttle body revised, and the exhaust openings redesigned. The exhaust manifold is also new, and a single silencer replaces the previous twin silencers.

In addition, there is an enlarged hydraulic clutch including reduced hand force as well as further weight-saving details such as a smaller fuel pump and an optimized magnesium cylinder head cover. The new plastic parts are also lighter and slimmer to support the driver’s freedom of movement. The seat has also been changed, it is now smaller and lower in the rear. An attractive new graphic design – completely in red – completes this comprehensive model update.

Thanks to narrower tubes, the main frame at 8.4 kg now weighs 700 g less than its predecessor, while a newly designed subframe now also saves 320 g at 910 g. The chassis dynamics are also new: While the torsional rigidity is retained, the lateral rigidity has been reduced by 20% in order to increase cornering speed, traction and steering accuracy. The aluminium swingarm has a new rigidity balance that is tailored to the frame, with narrower tubes and a pivot point. The Pro-Link ratio has also been revised.

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Both the upper and lower triple trees have been revised. They now offer more flex for faster steering and a better steering feel. The fully adjustable 49mm Showa USD suspension fork is a variation of the Showa “factory” fork that will be delivered to MX racing teams in the Japanese championship. The forks were revised with the aim of improved, softer cornering behaviour: the spring travel increased by 5 mm to 310 mm and the stiffness of the axle clamps was increased. The main piston valve of the Showa rear wheel shock absorber has been enlarged for faster response and improved shock absorption. Its spring also uses the lightest steel in the world – this saves another 200 g in weight.

The 2021 model of the CRF450R has a wide range of improvements and upgrades, all of which can be summarized under the development theme “razor-sharp steering”. First, the machine is 2 kg lighter thanks to a revised frame and subframe. In addition, the rigidity balance of the new frame and the swing arm in conjunction with a tighter chassis geometry, greater ground clearance and changes to the suspension are all geared towards optimal cornering behaviour. The findings from Tim Gajser’s 2019 World Champion season reduce driver fatigue and enable enthusiasts of all performance classes to achieve consistently optimal lap times. 

The engine also benefits from HRC’s know-how: it now places a strong focus on torque in the low to medium speed range. The decompression unit was relocated, the volume of the airbox increased, the throttle body revised, and the exhaust openings redesigned. The exhaust manifold is also new, and a single silencer replaces the previous twin silencers.

In addition, there is an enlarged hydraulic clutch including reduced manual force as well as further weight-saving details such as a smaller fuel pump and an optimized magnesium cylinder head cover. The new plastic parts are also lighter and slimmer to support the driver’s freedom of movement. The seat has also been changed, it is now smaller and lower in the rear. An attractive new graphic design – completely in red – completes this comprehensive model update.

The double loop aluminium frame of the CRF450R remained unchanged on the 2020 model. For the 2021 season, it was now completely renewed with direct input from the HRC racing team to improve every aspect of cornering behaviour.

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Thanks to narrower tubes, the main frame at 8.4 kg now weighs 700 g less than its predecessor, while a newly designed subframe now also saves 320 g at 910 g. The chassis dynamics are also new: while the torsional rigidity is retained, the lateral rigidity has been reduced by 20% in order to increase cornering speed, traction and steering accuracy. The aluminium swingarm has a new rigidity balance that is tailored to the frame, with narrower tubes and a pivot point. The Pro Link ratio has also been revised.

Both the upper and lower triple trees have been revised. They now offer more flex for faster steering and a better steering feel. The fully adjustable 49mm Showa USD suspension fork is a variation of the Showa “factory” fork that will be delivered to MX racing teams in the Japanese championship. The forks were revised with the aim of improving the softer cornering behaviour: the spring travel increased by 5 mm to 310 mm and the stiffness of the axle clamps was increased. The main piston valve of the Showa rear wheel shock absorber has been enlarged for faster response and improved shock absorption. Its spring also uses the lightest steel in the world – this saves another 200 g in weight.

The seat is now shorter, lighter and 10 mm lower at the back to support the driver’s freedom of movement. It is also much easier to remove and install. Maintenance has also been simplified as the number of 8mm screws securing bodywork has been reduced from 6 to 4 per side. The new machine is also 70 mm slimmer (50 mm on the left side, 20 mm on the exhaust side) and the plastic parts are thinner, and the tank cover was also saved.

The values for steering head angle and caster are now lower at 27.1 ° and 114 mm (previously 27.4 ° / 116 mm) and the wheelbase is also slightly shorter at 1481 mm (1482 mm). The ground clearance increases by 8 mm to 336 mm, and the lower triple clamp is now 6.1 mm higher at 928 mm. The radius from the swing arm pivot to the rear wheel axle mount increases by 0.9 ° to 14.5 °, while the distance between the pivot point and the front axle mount increases by 1.8 mm to 914.6 mm. The dry weight is 105.8 kg, which is a whole 2 kg lighter than that of the previous model.

The radiator cowls, designed with Computational Flow Dynamics (CFD) technology for maximum air flow, are now made from one instead of two plastic parts and have a lower vent, while the radiator grilles are optimized for airflow. The 6.3 litre titanium fuel tank has also been improved.

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A lightweight Fatbar Flex handlebar from Renthal is standard for optimum comfort. The upper triple clamp has two handlebar brackets with which the handlebar can be moved 26 mm back and front. If the holder is turned 180 °, the handlebar can be shifted a further 10 mm from the basic position, resulting in four individual riding positions. In terms of weight savings, many smaller amounts also lead to success (“A mountain can be formed from enough dust,” as a Japanese proverb says); In this sense, the machine cabling, which has now been optimized again, saves another 100 g.

At the front, a double-piston brake caliper with 30- and 27-mm piston diameters and a 260 mm wave disc is used. Together with the brake hose with a low expansion rate, the system offers both an optimal pressure point and maximum stability. The rear single-piston brake caliper works in conjunction with a 240 mm wave disc.

The DID aluminium rims are painted black; the front wheel rim is 21 x 1.6 inches, the rear wheel rim 19 x 2.15 inches. The rear wheel on the 2021 model is both stronger and lighter. Dunlop MX33F / MX33 cross tires are fitted as standard tires.

After an increase in output of 1.8 kW at the top, plus 2 Nm more torque and more power in the lower speed range for the 2019 model, the further development of the 449.7 ccm four-valve Unicam engine for 2020 focused on optimizing the PGM-FI -Mappings and the HRC launch control as well as the integration of the new traction control Honda Selectable Torque Control (HSTC). The new machine for 2021 focuses on upgrades that are derived directly from Tim Gajser’s HRC world champion machine: They bring significant improvements in driveability in the low to medium speed range as well as weight savings to further improve cornering performance.

A significant increase (up to 0.6 kW) in peak power above 5,000 rpm is accompanied by a more noticeable torque at low engine speeds, which is the result of an airbox enlarged by 1.8 l to 4.1 l. This is now easily accessible by removing a side panel screw and feeds a newly designed, lighter 46 mm throttle body. It optimizes the efficiency in the intake tract and actively uses the latent heat of vaporization that arises in the intake ducts.

The injector angle has been increased from 30 ° to 60 °, which means that the fuel is sprayed in the opposite direction to the intake air in the direction of the throttle valve. This improves the intake efficiency, the cooling of the mixture and the important “throttle valve feeling” for the driver. The decompression system is also new: its counterweight is shifted from the right side of the camshaft to the left, which means more stable operation at low engine speeds with less risk of death.

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