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Honda CRF450RX 2021

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Cross Country / Hare Scramble / Racing

2021 Honda CRF450RX

450cc

4-stroke

53.2hp

Measured power

251lb

Curb weight

37.8in

Seat height

12.2in

Front travel

2021 Honda CRF450RX at a glanceQuick facts

  • The 2021 Honda CRF450RX has a 450cc fuel-injected 4-stroke engine, a 5-speed gearbox and electric start.
  • The 2021 CRF450RX weighs 251 lb ready to ride and has a 37.8 in seat height.
  • The 2021 CRF450RX runs 90/90-21 front and 120/90-18 rear tires.
  • The 2021 CRF450RX takes 1.1 US qt (1.0 L) of 10W-30 engine oil; change it every 4 races or about 15 hours.
  • The 2021 CRF450RX lists at $9,899 (US MSRP). It is not street legal in the US.

About the 2021 Honda CRF450RXThe machine

The 2021 Honda CRF450RX is Honda's closed-course off-road racer: the CRF450R motocross bike adapted for cross-country, GNCC-style and hare scramble racing, with its own ECU map and suspension settings, an 18-inch rear wheel, Dunlop AT81 tires (90/90-21 front), handguards, an aluminum sidestand and a bigger 2.11-gallon fuel tank. Its fuel-injected, liquid-cooled 450cc single has a Unicam SOHC four-valve head, electric start and a five-speed gearbox with a hydraulic clutch, plus Honda Selectable Torque Control, HRC Launch Control and a handlebar map switch. Redesigned for 2021 with the CRF450R: an all-new frame, subframe and narrower swingarm, a revised cylinder head with a centralized exhaust port, a single muffler (it had two), a bigger airbox boot and a hydraulic clutch with an eighth plate, for about 4 lb less weight. New for the RX: standard handguards and a reshaped fuel tank that slims the bike at the radiator shrouds.

Who should ride it

For experienced riders who race cross-country, GNCC-style and hare scramble events on closed courses and want a 450 four-stroke set up for woods and rough terrain rather than a motocross track. It is a competition-only bike: not street legal in the US, and not meant for beginners.

2021 Honda CRF450RX photosGarage

01 / 02

2021 Honda CRF450RX specificationsTech specs

Engine
Displacement
450cc
Stroke
4-stroke
Fuel system
Fuel injection
Bore × stroke
96 × 62.1 mm
Compression
13.5:1
Power (measured)
53.2 hp at the rear wheel
Cooling
Liquid
Configuration
Single-cylinder
Valve train
SOHC
Valves
4
Engine oil
1.1 US qt (1.0 L)
Oil type
10W-30
Coolant
1.1 US qt (1.08 L)
Clutch
Type
Wet multiplate
Actuation
Hydraulic
Drivetrain
Starting
Electric
Transmission
5-speed
Chain size
520
Chain links
114
Front sprocket
13T
Rear sprocket
50T
Dimensions
Seat height
37.8″
Ground clearance
13.1″
Wheelbase
58.1″
Width
33″
Height
50.4″
Length
85.6″
Curb weight
251 lb
Fuel capacity
2.11 gal
Price & warranty
Destination charge
$380
Colors
Red
Warranty
Sold “as is” with no warranties.
Equipment
Honda Selectable Torque Control
Standard
HRC Launch Control
Standard
Handguards
Standard
Aluminum sidestand
Standard
Frame & steering
Frame material
Aluminum
Rake
27.3°
Trail
4.5″
Suspension
Front
49 mm inverted Showa coil-spring fork
Front travel
12.2″
Rear
Pro-Link Showa single shock
Rear travel
12.3″
Wheels & tires
Front wheel
21″
Rear wheel
18″
Front tire
Dunlop AT81F 90/90-21 54M
Rear tire
Dunlop AT81 120/90-18 65M
Brakes
Front disc
260 mm
Rear disc
240 mm
Stock features
Map switch
Yes
Skid plate
Yes
Street legal (US)
No
Battery / electrical
Battery
Yes
OEM battery
HY85S
Chemistry
Lithium
Voltage
12V
Capacity
2 Ah

2021 Honda CRF450RX maintenanceWrench time

From the maker's manuals. Tap a row to see the manual page it comes from.

Service intervals
Change engine oil
Every 4 races or about 15 hours
Replace oil filter
Every 4 races or about 15 hours
Clean air filter
Every race or about 3.5 hours
Inspect spark plug
Every race or about 3.5 hours
Change engine oil (first time)
After the first break-in ride
Replace oil filter (first time)
After the first break-in ride
Spark plug
Spark plug
NGK SILMAR10A-9S
Plug gap
0.031 – 0.035 in (0.80 – 0.90 mm)
Torque specs
Oil drain bolt
13 ft‑lb (18 N·m, 1.8 kgf·m)
Spark plug
16 ft‑lb (22 N·m, 2.2 kgf·m)
Front axle
65 ft‑lb (88 N·m, 9.0 kgf·m)
Front axle pinch bolts
15 ft‑lb (20 N·m, 2.0 kgf·m)
Rear axle nut
94 ft‑lb (128 N·m, 13.1 kgf·m)
Upper triple clamp bolts
16 ft‑lb (22 N·m, 2.2 kgf·m)
Lower triple clamp bolts
15 ft‑lb (20 N·m, 2.0 kgf·m)
Handlebar clamp bolts
16 ft‑lb (22 N·m, 2.2 kgf·m)
Front brake caliper mounting bolts
22 ft‑lb (30 N·m, 3.1 kgf·m)
Rear sprocket nuts
30 ft‑lb (40 N·m, 4.1 kgf·m)
Front sprocket bolt
23 ft‑lb (31 N·m, 3.2 kgf·m)
Chain adjuster locknut
20 ft‑lb (27 N·m, 2.8 kgf·m)
Shock absorber mounting bolts
32 ft‑lb (44 N·m, 4.5 kgf·m)

Parts for the 2021 Honda CRF450RXParts that fit

Exact parts for this bike. Tap one to see every store we found selling it, cheapest first.

Maintenance

Oil, filters, spark plug, battery, brakes and drive parts you replace as you ride.

Tires

Stock sizes, from the owner's manual.

Controls

Grips, and the throttle part each bike needs to fit them.

Prices include shipping where the store lists it and were checked Oct 31, 2026. Prices change, so confirm at the store before you buy.

Honda CRF450RX FAQPit-lane questions

  1. 01

    How much power does the 2021 Honda CRF450RX make?

    Dirt Rider measured 53.2 hp on its dyno.

  2. 02

    What engine does the 2021 Honda CRF450RX have?

    A fuel-injected, liquid-cooled 450cc single-cylinder four-stroke with a Unicam SOHC four-valve head and a five-speed gearbox.

  3. 03

    How is the 2021 Honda CRF450RX different from the CRF450R?

    It has its own ECU map and off-road suspension settings, a 90/90-21 front tire and an 18-inch rear wheel with Dunlop AT81 tires (the CRF450R runs an 80/100-21 front and a 19-inch rear). It also has handguards, an aluminum sidestand and a bigger 2.11-gallon fuel tank.

  4. 04

    What is the seat height of the 2021 Honda CRF450RX?

    37.8 in.

  5. 05

    How much does the 2021 Honda CRF450RX weigh?

    Honda lists a curb weight of 251 lb, ready to ride with a full tank.

  6. 06

    How much suspension travel does the 2021 Honda CRF450RX have?

    12.2 in at the front and 12.3 in at the rear.

  7. 07

    How much fuel does the 2021 Honda CRF450RX hold?

    2.11 US gal (8.0 L).

  8. 08

    What oil does the 2021 Honda CRF450RX take?

    SAE 10W-30 motorcycle oil (JASO MA), 1.1 US qt (1.0 L) after draining.

  9. 09

    Is the 2021 Honda CRF450RX street legal?

    No. It is sold for closed-course competition only and is not street legal in the US.

  10. 10

    What was the MSRP of the 2021 Honda CRF450RX?

    $9,899, plus a $380 destination charge.

  11. 11

    What size tires does the 2021 Honda CRF450RX use?

    90/90-21 front and 120/90-18 rear.

  12. 12

    What spark plug does the 2021 Honda CRF450RX take?

    NGK SILMAR10A-9S, gapped 0.031 – 0.035 in (0.80 – 0.90 mm).

  13. 13

    What chain and sprockets does the 2021 Honda CRF450RX use?

    A 520 chain with 114 links on a 13-tooth front and 50-tooth rear sprocket.

Specs from Honda's owner's and service manuals, Honda's website and published spec sheets. Updated . Spot a mistake?

Other Honda CRF450RX model yearsOther seasons

2021202220232024202520262027