21YM HONDA CRF450RX
Like the CRF450R - every part of the CRF450RX is new for 2021, save for wheels and engine, with the comprehensive update benefiting directly from knowhow gained by the development of Tim Gajser and HRC’s 2019 championship-winning CRF450RW works machine. Its 2.3kg lighter and features a new frame and swingarm, plus changes to geometry and suspension, greatly improve cornering performance. The engine receives intake/exhaust upgrades, new decompression system plus single exhaust muffler to boost and smoothen low-mid-range driveability. A larger hydraulic clutch offers greater control with lighter lever pressure. More compact plastics and a smaller seat unit increase freedom of movement. Brush guards are now standard-fit and the sidestand tucks in more neatly for improved rider ergonomics.
21YM sees a major evolution for the CRF450RX. Starting from the exact same point as the 21YM CRF450R (which has been almost totally redesigned by HRC with developments taken directly from Tim Gajser’s 2019 MXGP championship-winning machine) it’s an even more formidable off-road weapon, devastatingly fast over the ground and, as importantly, with high build quality and reliability that makes it easy to live with over the years of ownership.
For 21YM, like its motocross sibling, the CRF450RX receives a wide array of improvements under a development theme of ‘The ultimate off-road weapon'. Firstly it’s 2.3kg lighter thanks to a revised frame and subframe. The new frame and swingarm’s rigidity balance, combined with tighter chassis geometry, heightened ground clearance and suspension changes, are all targeted at creating optimal cornering performance.
The engine also benefits from HRC’s knowhow to give a strong focus on low- to mid-range torque. The decompressor has been relocated, airbox volume is up, the throttle body redesigned and exhaust ports re-shaped. The exhaust downpipe is new and a single muffler replaces dual mufflers.
A larger-volume hydraulic clutch has an even lighter lever action, while other weight-saving details include a smaller fuel pump and optimised magnesium cylinder head cover. New plastics, too, are lighter and slimmer to aid rider freedom and the seat is a smaller unit, lower at the back. Brush guards are now standard fit and the sidestand tucks away more neatly. A smart new all-red graphic scheme completes this major update.

Chassis
• Narrower swing arm spars and swingarm pivot point, with revised swingarm rigidity balance
• Geometry changes combine with the above to improve cornering ability
• Re-valved front suspension with an extra 5mm stroke matched with re-valved rear shock
• Improved ergonomics from smaller new seat, and more compact, redesigned plastics

Engine
• Larger airbox plus revised throttle body and exhaust ports for bottom-end drive
• New exhaust downpipe with single muffler boosts torque and saves weight
• Larger volume hydraulic clutch replaces cable operation for consistent and light lever feel
• Revised decompressor system gives improved stall resistance

Electronics
• Honda Selectable Torque Control (HSTC) with 3 riding modes (plus OFF)
• HRC Launch Control offers 3 start options
• Engine Mode Select Button (EMSB) features 3 maps to adjust output character
• HSTC button now rationalised into the left-hand switchgear
• HRC Setting tool updated for changes to Aggressive and Smooth modes

Technical Specifications
ENGINE
Type
Liquid-cooled 4-stroke single cylinder uni-cam
Displacement
449.7cc
Bore ´ Stroke
96.0mm x 62.1mm
Compression Ratio
13.5: 1

FUEL SYSTEM
Carburation
Fuel injection
Fuel Tank Capacity
8 litres

ELECTRICAL SYSTEM
Ignition
Digital CDI
Starter
Self-Starter

DRIVETRAIN
Clutch Type
Wet type multi-plate
Transmission Type
Constant mesh
Final Drive
Chain

FRAME
Type
Aluminium twin tube
Dimensions (L´W´H)
2,182 x 839 x 1,282mm
Wheelbase
1,481mm
Caster Angle
27.1°
Trail
114mm
Seat Height
965mm
Ground Clearance
336mm
Kerb Weight
107.6kg

SUSPENSION
Type Front
Showa 49mm USD fork
Type Rear
Showa monoshock using Honda Pro-Link 

WHEELS
Type Front
Aluminium spoke
Type Rear
Aluminium spoke
Tyres Front
90/90-21M Dunlop Geomax AT81F
Tyres Rear
120/90-18M Dunlop Geomax AT81

BRAKES
Front
Single 260mm disk
Rear
Single 240mm disk