2021 KTM 50 SX Specifications

Name: 2021 KTM 50 SX
Brand: KTM

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2021 KTM 50 SX Overview

The 2021 KTM 50 SX is a minibike, cross motorcycle built around 49 cc of displacement. Under the tank sits a Single cylinder, two-stroke engine running Double Overhead Cams/Twin Cam (DOHC) valve actuation. The bore and stroke measures 39.5 x 40 mm. From a practical standpoint, the 2021 50 SX tips the scales at 41.5 kg, carries a 2.30-litre fuel tank and offers a seat height of 684 mm. Scroll down for the complete 2021 KTM 50 SX spec sheet covering every technical detail from suspension travel to tyre sizes.

2021 50 SX - Pros & Cons

Strengths

Accessible seat height: At 684 mm, the seat height is approachable for a wide range of rider heights and builds confidence in low-speed manoeuvring.

Considerations

Age-related wear: As with any used 50 SX, a thorough pre-purchase inspection covering consumables, service history and tyres is always recommended.

Owner Experiences & Common Issues

Valve clearance checks

Double Overhead Cams/Twin Cam (DOHC) 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.

50 SX - Buying & Maintenance Guide

What to check before buying

When inspecting a used 2021 KTM 50 SX, 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 50 SX 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 50 SX. 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.

Valve clearance service

Check that valve clearances have been adjusted at the correct intervals on any used 50 SX. 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 50 SX - Frequently Asked Questions

What engine does the 2021 KTM 50 SX have?

The 2021 KTM 50 SX uses a Single cylinder, two-stroke engine with 49 cc of displacement.

How much does the 2021 KTM 50 SX weigh?

The 2021 KTM 50 SX weighs 41.5 kg. This is the manufacturer's dry figure.

What is the fuel tank capacity of the 2021 KTM 50 SX?

The 2021 KTM 50 SX has a 2.30-litre fuel tank.

Is the 2021 KTM 50 SX suitable for shorter riders?

The 2021 KTM 50 SX has a seat height of 684 mm. This is a comfortable, accessible height for most riders.

What brakes does the 2021 KTM 50 SX have?

The 2021 KTM 50 SX uses Single disc at the front and Single disc at the rear.

What suspension does the 2021 KTM 50 SX have?

The 2021 KTM 50 SX uses XACT 35 WP Upside-Down fork, Ø 35 mm up front and XACT WP mono shock at the rear.

What frame does the 2021 KTM 50 SX use?

The 2021 KTM 50 SX is built around a 25CrMo4 steel central-tube frame frame.

KTM 50 SX Spec Evolution

The KTM 50 SX was produced across 17 model years (2006-2023). 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	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	2021	2022	2023
Wet Weight	-	-	-	-	-	104.0 kg / 229.3 lbs	-	-	112.0 kg / 246.9 lbs	-	-	-	-	-	-	-	-
Dry Weight	38.8 kg / 85.5 lbs	38.8 kg / 85.5 lbs	38.8 kg / 85.5 lbs	39.8 kg / 87.7 lbs	39.8 kg / 87.7 lbs	39.8 kg / 87.7 lbs	41.5 kg / 91.5 lbs	41.5 kg / 91.5 lbs	39.8 kg / 87.7 lbs	39.8 kg / 87.7 lbs	41.5 kg / 91.5 lbs	41.5 kg / 91.5 lbs	41.5 kg / 91.5 lbs	41.5 kg / 91.5 lbs	41.5 kg / 91.5 lbs	41.5 kg / 91.5 lbs	41.5 kg / 91.5 lbs
Engine Detail	-	-	-	-	-	-	Reed intake	Reed intake.	Reed intake.	Reed intake.	Reed intake.	Reed intake.	Reed intake	Reed intake	-	-	-
Engine Type	Single cylinder	Single cylinder	Single cylinder	Single cylinder	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke	Single cylinder, two-stroke
Seat Height	650 mm / 25.6 in.	650 mm / 25.6 in.	660 mm / 26.0 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	684 mm / 26.9 in.	665 mm / 26.2 in.	665 mm / 26.2 in.
Fuel Capacity	1.80 litres / 0.48 gallons	1.80 litres / 0.48 gallons	1.80 litres / 0.48 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 gallons	2.30 litres / 0.61 US gallons	2.30 litres / 0.61 US gallons	2.30 litres / 0.61 US gallons	2.30 litres / 0.61 US gallons
Stroke	2	2	2	2	-	-	-	-	-	-	-	-	-	-	-	-	2-stroke
Ground Clearance (mm)	255 mm	255 mm	255 mm	255 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm	252 mm

Key Specifications

Engine

Single cylinder, two-stroke

Power

N/A

Torque

N/A

Top Speed

N/A

Weight

41.5 kg / 91.5 lbs

Fuel Capacity

2.30 litres / 0.61 US gallons

Full 2021 KTM 50 SX Specifications

Colours White/Orange

Bore x Stroke (in,) 1.6 x 1.6 inches

Bore x Stroke (mm) 39.5 x 40.0 mm

Displacement (cc) 49.0 cc

Displacement (ci) 2.99 cubic inches

Engine Type Single cylinder, two-stroke

Fuel Control Double Overhead Cams/Twin Cam (DOHC)

Starter Kick

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2021 KTM 50 SX Specifications

2021 KTM 50 SX Overview

2021 50 SX - Pros & Cons

Strengths

Considerations

Owner Experiences & Common Issues

Valve clearance checks

50 SX - Buying & Maintenance Guide

What to check before buying

Oil and filter changes

Valve clearance service

2021 KTM 50 SX - Frequently Asked Questions

KTM 50 SX Spec Evolution

Key Specifications

Full 2021 KTM 50 SX Specifications

Compare KTM 50 SX

50 SX Years

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KTM 50 SX - other years