2021 CRF450RX



Model updates: 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.


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  • 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


  • 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


  • 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

The three Modes differ in drive management level for different riding conditions:

  • In Mode 1 the system intervenes most lightly, and after the longest time ­– useful for reducing wheelspin and maintaining control in tight corners.
  • Mode 2 naturally offers a mid-point between 1 and 3 in terms of speed and strength of intervention.
  • Mode 3 has the system intervene more quickly and strongly, and is therefore useful in more slippery, muddy conditions.

HRC Launch Control gives any rider the best option for a strong start and also has 3 modes to choose from:

  • Level 3 – 8,250rpm, muddy conditions/novice.
  • Level 2 – 8,500rpm, dry conditions/standard.
  • Level 1 – 9,500rpm, dry conditions/expert.

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.



Type Liquid-cooled 4-stroke single cylinder uni-cam
Displacement 449.7cc
Bore ´ Stroke 96.0mm x 62.1mm
Compression Ratio 13.5: 1
Carburation Fuel injection
Fuel Tank Capacity 8 litres
Ignition Digital CDI
Starter Self-Starter
Clutch Type Wet type multi-plate
Transmission Type Constant mesh
Final Drive Chain
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
Type Front Showa 49mm USD fork
Type Rear Showa monoshock using Honda Pro-Link
Type Front Aluminium spoke
Type Rear Aluminium spoke
Tyres Front 90/90-21M Dunlop Geomax AT81F
Tyres Rear 120/90-18M Dunlop Geomax AT81
Front Single 260mm disk
Rear Single 240mm disk
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