MotoSpecs

2021 KTM 450 SX-F Specifications

Cross / motocross

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2021 KTM 450 SX-F Overview

The 2021 KTM 450 SX-F is a cross / motocross motorcycle built around 449.3 cc of displacement. Under the tank sits a Single cylinder, four-stroke engine running Single Overhead Cams (SOHC) valve actuation. The bore and stroke measures 95 x 63.4 mm. From a practical standpoint, the 2021 450 SX-F tips the scales at 100 kg, carries a 7-litre fuel tank, offers a seat height of 950 mm and spans a 1485 mm wheelbase. Scroll down for the complete 2021 KTM 450 SX-F spec sheet covering every technical detail from suspension travel to tyre sizes.

2021 450 SX-F - Pros & Cons

Strengths

  • Fuel injection: The fuel injection injection system delivers crisp throttle response and reliable cold starts regardless of altitude or temperature.

Considerations

  • Tall seat height: The 950 mm seat height will challenge shorter riders - tiptoeing at low speeds is something to factor into your decision.

Owner Experiences & Common Issues

Throttle response and fuelling

The fuel injection on the 2021 KTM 450 SX-F is generally well-regarded. Some owners note a slight hesitation at small throttle openings when cold, which clears once the engine reaches operating temperature. A quick visual check of the injector connectors during routine servicing is good practice on higher-mileage examples.

Valve clearance checks

Single Overhead Cams (SOHC) engines should have valve clearances checked at the manufacturer's specified interval. Owners report that clearances can tighten over time on higher-mileage bikes, leading to slight ticking from the top end. Catching it early keeps the job simple and avoids more costly remediation.

450 SX-F - Buying & Maintenance Guide

What to check before buying

When inspecting a used 2021 KTM 450 SX-F, start with the basics: check the service book for oil change frequency, inspect the chain and sprockets for wear, and look for oil seepage around the engine casings and rocker covers. A cold start test is invaluable - a well-maintained 450 SX-F should fire up cleanly and settle to a smooth idle within a few seconds.

Oil and filter changes

Regular oil changes are the single most important maintenance task on any 450 SX-F. Stick to the manufacturer's interval - typically every 6,000 km or once a year, whichever comes first. Always use the correct viscosity grade as specified in the owner's manual.

Fuel system care

The 450 SX-F's fuel injection system is durable but benefits from quality fuel and the occasional use of a fuel-system cleaner additive. If the bike has been stored for more than three months, drain and replace the fuel to prevent varnish deposits in the injectors.

Valve clearance service

Check that valve clearances have been adjusted at the correct intervals on any used 450 SX-F. This is a job many owners skip because the bike does not immediately feel wrong - but tight clearances accelerate valve seat wear. Ask for proof it has been done.

2021 KTM 450 SX-F - Frequently Asked Questions

What engine does the 2021 KTM 450 SX-F have?
The 2021 KTM 450 SX-F uses a Single cylinder, four-stroke engine with 449.3 cc of displacement.
How much does the 2021 KTM 450 SX-F weigh?
The 2021 KTM 450 SX-F weighs 100 kg. This is the manufacturer's dry figure.
What is the fuel tank capacity of the 2021 KTM 450 SX-F?
The 2021 KTM 450 SX-F has a 7-litre fuel tank.
Is the 2021 KTM 450 SX-F suitable for shorter riders?
The 2021 KTM 450 SX-F has a seat height of 950 mm. This is towards the tall end of the spectrum and will require most riders under 175 cm to tiptoe at stops.
What brakes does the 2021 KTM 450 SX-F have?
The 2021 KTM 450 SX-F uses Single disc. Brake calipers on floating bearings at the front and Single disc. Brake calipers on floating bearings at the rear.
What fuel system does the 2021 KTM 450 SX-F use?
The 2021 KTM 450 SX-F uses Injection, providing precise fuelling across the rev range and reliable cold-start behaviour.
What suspension does the 2021 KTM 450 SX-F have?
The 2021 KTM 450 SX-F uses WP XACT-USD, Ø 48 mm up front and WP XACT Monoshock with linkage at the rear.

KTM 450 SX-F Spec Evolution

The KTM 450 SX-F was produced across 16 model years (2007-2023). The table below highlights the key specifications that changed across the production run - useful whether you are comparing years or tracking down a specific variant.

Specification 2007 2008 2009 2010 2011 2012 2013 2015 2016 2017 2018 2019 2020 2021 2022 2023
Dry Weight 104 kg / 229.3 lbs 104.6 kg / 230.6 lbs 104.6 kg / 230.6 lbs 104.6 kg / 230.6 lbs 106.9 kg / 235.7 lbs 107.8 kg / 237.7 lbs 106.2 kg / 234.1 lbs 105.5 kg / 232.6 lbs 100.4 kg / 221.3 lbs 100.2 kg / 220.9 lbs 100.2 kg / 220.9 lbs 100 kg / 220.5 lbs 100 kg / 220.5 lbs 100 kg / 220.5 lbs 100.5 kg / 221.6 lbs 102.6 kg / 226.2 lbs
Engine Type Single cylinder Single cylinder Single cylinder Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke Single cylinder, four-stroke
Seat Height 925 mm / 36.4 in. 960 mm / 37.8 in. 985 mm / 38.8 in. 985 mm / 38.8 in. 992 mm / 39.1 in. 992 mm / 39.1 in. 992 mm / 39.1 in. 992 mm / 39.1 in. 960 mm / 37.8 in. 960 mm / 37.8 in. 960 mm / 37.8 in. 960 mm / 37.8 in. 950 mm / 37.4 in. 950 mm / 37.4 in. 950 mm / 37.4 in. 958 mm / 37.7 in.
Fuel Capacity 8.00 litres / 2.11 gallons 8.20 litres / 2.17 gallons 8.00 litres / 2.11 gallons 8.00 litres / 2.11 gallons 7.50 litres / 1.98 gallons 7.50 litres / 1.98 gallons 7.50 litres / 1.98 gallons 7.50 litres / 1.98 gallons 7.00 litres / 1.85 gallons 7.00 litres / 1.85 gallons 7.00 litres / 1.85 gallons 7.00 litres / 1.85 US gallons 7.00 litres / 1.85 US gallons 7.00 litres / 1.85 US gallons 7.50 litres / 1.98 US gallons 7.20 litres / 1.90 US gallons
Bore x Stroke (in,) 3.8 x 2.4 inches 3.8 x 2.4 inches 3.8 x 2.4 inches 3.8 x 2.4 inches 3.8 x 2.4 inches 3.8 x 2.4 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches 3.7 x 2.5 inches
Bore x Stroke (mm) 97.0 x 60.8 mm 97.0 x 60.8 mm 97.0 x 60.8 mm 97.0 x 60.8 mm 97.0 x 60.8 mm 97.0 x 60.8 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm 95.0 x 63.4 mm
Displacement (cc) 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.30 cc 449.3 cc 449.3 cc 449.3 cc 449.3 cc 449.9 cc
Displacement (ci) 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.42 cubic inches 27.45 cubic inches

Key Specifications

Engine

Single cylinder, four-stroke

Power

N/A

Torque

N/A

Top Speed

N/A

Weight

100 kg / 220.5 lbs

Fuel Capacity

7.00 litres / 1.85 US gallons

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Full 2021 KTM 450 SX-F Specifications

Colours Orange/white/black
Power-to-Weight Ratio 0.6300 HP/kg
Bore x Stroke (in,) 3.7 x 2.5 inches
Bore x Stroke (mm) 95.0 x 63.4 mm
Displacement (cc) 449.3 cc
Displacement (ci) 27.42 cubic inches
Engine Type Single cylinder, four-stroke
Fuel Control Single Overhead Cams (SOHC)
Fuel System Injection
Ignition Keihin EMS
Starter Electric
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