2021 KTM 50 SX Specifications

Name: 2021 KTM 50 SX
Brand: KTM

Minibike, cross • Specs last verified 13 July 2026

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2021 KTM 50 SX Overview

KTM 50 SX is a minibike, cross motorcycle, displacing 49 cc. Power comes from a Single cylinder, two-stroke engine running Double Overhead Cams/Twin Cam (DOHC) valve actuation. Bore and stroke come in at 39.5 x 40 mm. On the road, 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. The full 2021 KTM 50 SX spec sheet below covers every technical detail, from suspension travel to tyre sizes.

2021 50 SX - Pros & Cons

Strengths

Accessible seat height: A 684 mm seat height keeps this manageable for most riders, which helps confidence at parking-lot speeds.

Considerations

Modest fuel capacity: Range between stops is limited by the 2.30-litre tank - plan fuel stops accordingly on longer routes.
Chain final drive upkeep: Budget time for routine chain maintenance - it's cheap to replace but needs consistent attention to avoid premature sprocket wear.

Wear Points & Servicing Notes

Valve clearance checks

With Double Overhead Cams/Twin Cam (DOHC) valve gear, the 50 SX needs periodic clearance checks; caught early they're a cheap adjustment, left unchecked they accelerate valve seat wear.

Brake disc and pad wear

Braking up front comes from Single disc - solid stopping power, with disc and pad wear best checked on the same schedule as tyre changes.

Suspension condition on used examples

The 50 SX's suspension runs XACT 35 WP Upside-Down fork, Ø 35 mm at the front. The rear uses XACT WP mono shock. Fork-seal condition and rear linkage play are the two things worth checking before buying used.

Final drive maintenance

The 50 SX uses chain final drive, which is cheap to replace but needs regular cleaning, lubrication and tension checks to get a full service life out of the sprockets.

Frame & chassis check

Built around a 25CrMo4 steel central-tube frame, the 50 SX's chassis is straightforward to inspect: look for corrosion, cracks or repair welds around stress points like the head-stock and swingarm mounts.

Low-speed handling

41.5 kg keeps the 50 SX easy to move around in tight spaces, car parks and on the stand alike.

50 SX - Buying & Maintenance Guide

What to check before buying

Before handing over money for a used 2021 KTM 50 SX, cover the fundamentals: service book and oil change history, chain and sprocket wear, and any sign of oil weeping around the casings. Cold-starting it yourself tells you a lot - a healthy 50 SX should catch quickly and settle into a smooth idle.

Oil and filter changes

Nothing protects a 50 SX's engine like disciplined oil changes - stay on the manufacturer's schedule (roughly every 6,000 km or annually). Match the viscosity grade to what the owner's manual specifies, not what's cheapest.

Valve clearance service

Valve clearances are easy to overlook on a used 50 SX since a bike out of spec doesn't always feel obviously wrong - but the wear it causes is real. Ask the seller for documentation before assuming it's 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. At around 5-6 litres per 100 km, that is roughly 38-45 km between stops.

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

Not published by manufacturer

Torque

Not published by manufacturer

Top Speed

Not published by manufacturer

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

Ground Clearance (in.) 9.9 inches

Ground Clearance (mm) 252 mm

Seat Height 684 mm / 26.9 in.

Dry Weight 41.5 kg / 91.5 lbs

Fuel Capacity 2.30 litres / 0.61 US gallons

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

Clutch Centrifugal

Final Drive Chain (final drive)

Gearbox Automatic

Frame Type 25CrMo4 steel central-tube frame

Suspension - Front XACT 35 WP Upside-Down fork, Ø 35 mm

Suspension - Rear XACT WP mono shock

Rake 24.0°

Wheel Travel - Front 205 mm / 8.1 in.

Wheel Travel - Rear 180 mm / 7.1 in.

Brakes - Front Single disc

Brakes - Rear Single disc

Specifications are compiled from manufacturer documentation and cross-referenced technical sources, and corrected on an ongoing basis. Spot an error? Let us know.

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2021 KTM 50 SX Specifications

2021 KTM 50 SX Overview

2021 50 SX - Pros & Cons

Strengths

Considerations

Wear Points & Servicing Notes

Valve clearance checks

Brake disc and pad wear

Suspension condition on used examples

Final drive maintenance

Frame & chassis check

Low-speed handling

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