For motocross enthusiasts who demand the absolute best when it comes to performance, the premium CRF450RWE ("Works Edition") benefits from the same improvements as the 2021 CRF450R, plus a long list of elite-level updates based on the machines in the Team Honda HRC factory race shop. As with the CRF450R, this model is endowed with important updates aimed at improving power, handling and consistency and—befitting its status as the clear benchmark when it comes to lap times—it boasts additional features aimed at refining power, suspension performance and aesthetics. New for 2021, the CRF450RWE now comes standard with a Hinson clutch basket and cover, as well as a Twin Air air filter.
OBJECTIVES
As they did with the CRF450R, Honda engineers identified "Razor Sharp Cornering" as their development theme as they approached the 2021 CRF450RWE project. In turn, this led to three main goals: Improve power, improve handling and improve consistency. The first point was addressed by making changes intended to increase the engine's horsepower and torque, particularly in the bottom end of the rpm range. The second objective was addressed by optimizing chassis rigidity, altering geometry and reducing vehicle weight. The final goal—regular, steady performance (by both the machine and the rider)—was pursued via updates to the clutch, as well as the vehicle layout for improved rider movement.
As is often the case, benefits overlapped, with improvements in one area leading to benefits in other areas. For example, the power and torque increase result in changes to power delivery that make the machine more manageable in corners. Similarly, the reduced weight not only aids cornering, but promotes a more consistent performance by the rider over the course of a race.
Speaking of weight savings, the reduction here is an example of something that was only achievable during an overall redesign, and only by accumulating small benefits in myriad areas. As the Japanese saying goes, "With enough dust, a mountain can form," and in this case the mountain was represented by a 4 pound overall weight reduction compared to last year's model.
ENGINE / DRIVETRAIN
The CRF450RWE engine has undergone a number of significant updates aimed at improving bottom-end and midrange power, making for a linear delivery that is strong but manageable, even as the rider tires. In addition, peak power is up .8 horsepower, above 5,000 rpm.
Head
As with the CRF450R, the design of the Unicam® cylinder head has been updated, with the decompressor system's counterweight relocated from the right end of the camshaft to the left. This improves combustion stability in the extremely low rpm range and contributes to a strong-but-manageable power delivery in corner exits, for example, as well as resistance to stalling. The magnesium cylinder head cover has also been designed with a thinner material, for weight savings.
The CRF450RWE also has a unique cylinder head with factory hand-polished ports for refined power characteristics. The exhaust port has been centralized, ovalized and straightened, achieving improved exhaust efficiency and revised torque characteristics, for a linear delivery that continues into the high rpm range.
As before, a five-hole piston oil jet and dual 12 mm drum scavenge pump manage lubrication.
Intake
The CRF450RWE features a downdraft intake design that delivers strong, efficient power, but the air boot has been drastically enlarged (from 1.8 liters on the clean side of the air filter to 4.1 liters), and for 2021, the bike now comes standard with a Twin Air air filter. The air box is now accessed with the removal of a single side-panel bolt.
The angle of the fuel injector has been increased from 30º to 60º, enabling the spray to reach all the way to the back of the butterfly, thus cooling the upstream side of the intake path, improving intake efficiency and torque feel.
In addition, the fuel pump is now smaller and 120 grams lighter. It's affixed via a simplified mounting system using only four fasteners instead of six. Fuel pressure and filter life are both unaffected.
Exhaust
The CRF450RWE boasts a lightweight full titanium Yoshimura exhaust system (header and muffler), and like the CRF450R, the system has switched from two mufflers to one, reducing weight and improving bottom-end torque delivery. The entire exhaust system now weighs 7.15 pounds, a reduction of 1.6 pounds from the previous model.
With the engine's new centralized exhaust-port location, the exhaust header is routed 74 mm closer to the engine on the right side, while the single, right-side muffler has also been reshaped to move its outer surface 13 mm inboard. The combined result is a slimmer overall vehicle body (including external parts), contributing to freedom of movement for the rider.
Two resonators (one after the front U-bend and another at the upstream end of the muffler) boost power and reduce noise, and the heat shield has been eliminated to reduce weight.
Clutch
With an eye toward increasing clutch durability, engineers increased clutch volume by 27% while also adding an eighth clutch plate and using stiffer springs. In addition, a friction spring was added to suppress resonance and greatly improve power delivery. These changes also reduce clutch slip by 85% at peak power, as measured by a chassis dynamometer. The clutch basket and cover are from Hinson to mirror the components from the Team Honda HRC race bikes.
To facilitate clutch actuation and encourage consistent performance, a hydraulic clutch is now utilized. As a result, the force needed to pull the handlebar lever is reduced. Depending on where in the lever stroke the measurement is taken, the reduction can be as much as 10% compared to the previous model, even with the stiffer springs.
Electronics
A gear-position sensor allows the use of three specific ignition maps for first and second, third and fourth, and fifth gears. There are also options for Standard, Smooth and Aggressive ignition maps, selectable via a redesigned handlebar-mounted switch, enabling simple tuning depending on rider preference or course conditions.
In addition, Honda Selectable Torque Control still offers three levels of intervention. HSTC monitors rpm spikes and responds by temporarily reducing torque by retarding ignition timing and controlling PGM-FI to aid rear traction. The three different modes differ in drive-management level, for differing riding conditions or rider preferences:
- Mode 1: The system intervenes most lightly and waits the longest to do so—useful for reducing wheel-spin and maintaining control in tight corners.
- Mode 2: A midpoint between modes 1 and 3 in terms of how quickly and assertively the system intervenes.
- Mode 3: The system intervenes most quickly and assertively, which helps in conditions that are slippery or muddy.
The handlebar-mounted switch allows selection between three modes, depending on conditions and rider preference. The HSTC system can also be switched off completely.
HRC Launch Control provides the best option for a strong start and also has three modes to choose from:
- Level 1: 9,500 rpm, for high-traction conditions and/or advanced riders
- Level 2: 8,500 rpm, for high-traction conditions and/or average riders
- Level 3: 8,250 rpm, for slippery conditions and/or novice riders
The Engine Mode Select Button (EMSB) alters the engine's characteristics and three maps are available to suit riding conditions or rider preference:
- Mode 1: Standard
- Mode 2: Smooth
- Mode 3: Aggressive
CHASSIS / SUSPENSION
A number of significant chassis revisions were incorporated in order to improve cornering. With these changes, geometry is now different: Wheelbase is now 1 mm shorter (at 58.3 inches), rake is .3º steeper (at 27.7º), trail is reduced by 2 mm (now 114 mm), the swingarm angle is .9º steeper (at 14.5º), the seat height is 5 mm taller (at 38.0 inches), ground clearance is increased by 8 mm (now 13.2 inches), and the distance from the front axle to the swingarm pivot is 1.8 mm longer (at 36.0 inches). As before, the vehicle's heavier components are positioned centrally and as low as possible.
The result is improved cornering without sacrificing high-speed tracking, in addition to reduced squat under acceleration and less pitching during hard braking.
Frame / Swingarm / Subframe
As with the 2021 CRF450R, the CRF450RWE's all-new frame features narrower main spars, a redesigned downtube and features rearranged reinforcement ribbing on the backside of the pivot plate, changes that contribute to an overall weight reduction of 1.54 pounds, with the new frame weighing just 18.5 pounds. Lateral rigidity is reduced by 20%—resulting in supple feel that improves cornering—while vertical rigidity is maintained.
The subframe features a simplified design that enabled the elimination of a separate seat support, achieving an overall weight of just 2.0 pounds—over .7 pounds down from before.
In addition, the swingarm is now narrower, providing increased clearance in ruts, with rebalanced rigidity tuned to match the frame and improve rear traction and cornering.
Suspension
As before, front suspension comprises a 49 mm inverted Showa® coil-spring fork that has a 25 mm piston and follows the basic structure of that on the 2020 CRF450RWE, and a gas-liquid separation structure, but suspension stroke has been increased by 5 mm to better absorb rough terrain while also reducing pitching. Compared to the CRF450R, the CRF450RWE's lower fork legs are coated in titanium nitride to minimize stiction and promote smooth action.
The axle holders have an updated design for increased rigidity. The upper and lower triple clamps have both been redesigned as well, with rigidity rebalanced via updated reinforcement ribs, delivering increased flex characteristics for improved handling and feel through a corner.
The Pro-Link® rear-suspension system uses a Showa shock absorber whose shape has been adapted to work with the new frame, with adjusters moved from the left side to the right. Weight was cut here as well, by switching to an ultra-light steel shock spring.
The link ratio and rear travel has also been changed so that acceleration-triggered rear-end squat is reduced.
Wheels
The CRF450RWE has special D.I.D DirtStar LT-X rims that are even stouter than the standard D.I.D rims of the CRF450R. Petal-style brake rotors disperse heat, and a low-expansion front brake hose gives strong feel and consistent stopping power, while a special gold RK chain delivers power to the rear wheel.
The 2021 CRF450R comes with Dunlop's excellent Geomax MX33 tires, generally considered to be the industry standard for soft to intermediate terrain. Developed with the help of top motocross pros, MX33s feature technologies that deliver superior grip, slide control, bump absorption and durability.
DESIGN
The technical changes to the CRF450RWE enabled the adaptation of slimmer bodywork, which facilitates rider movement. For example, the lack of a left-side muffler made possible a side panel that is 50 mm more inboard, and even the right side panel is moved 20 mm inboard thanks to the new muffler shape. Together, the changes result in a 70 mm reduction in width at the rear of the bike, substantially benefitting rider movement—and, consequentially, cornering. The junction of the radiator shroud and the side panel is smoother as well, further aiding rider movement.
The radiator shrouds are new as well, and each is now produced in a single piece instead of two separate parts. Computational Fluid Dynamics (CFD) were used to design new air-outlet vents in the shrouds. The radiator grills have also been revised to optimize the number of fins and their angle, resulting in a 5% improvement in cooling performance, without changing vehicle width at the shrouds.
Whereas the seat was previously installed by sliding it forward onto the subframe and then securing it at the rear, the new seat base has rearward-facing tongues and front-located mounting tabs. This eases installation, and acceleration forces keep the seat securely in place. Compared to the CRF450R, the Works Edition version has a special Throttle Jockey gripper seat cover. The 1.7 gallon fuel tank is once again made of lightweight titanium but has a new design, and the plastic tank cover has been eliminated.
During the model's redesign, engineers looked for and capitalized upon every opportunity to cut weight for improved handling. For example, only 8 fasteners are used to secure all of the main bodywork components—both radiator shrouds, both side panels and the seat—instead of 12 as before. In addition, all of the bolts for the main bodywork parts now have 8 mm heads, simplifying maintenance.
A further 98 grams were cut by combining what used to be two left-side handlebar switch assemblies into a single cluster that addresses several functions: engine stop, ride-modes and Honda Selectable Torque Control (HSTC). The starter and HRC launch control are on the right side of the Renthal® Fatbar® handlebar, which sports special Renthal dual-compound grips on the CRF450RWE. As before, there are two locations for the handlebar clamp, and the clamp can be turned 180º; as a result, four different mounting positions are possible, through a range of 26 mm. Routing the throttle and clutch control cables behind the handlebar instead of in front allowed for a weight reduction of 100 grams high on the bike.
Rounding out the package are Throttle Jockey graphics, straight off the Team Honda HRC factory machines of Ken Roczen and Chase Sexton.
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