2023 KTM 125 SX Specifications

Name: 2023 KTM 125 SX
Brand: KTM

Enduro / Off-Road • Specs last verified 13 July 2026

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2023 KTM 125 SX Overview

The 2023 KTM 125 SX is an enduro / off-road motorcycle built around 124.8 cc of displacement. Under the tank sits a Single cylinder, two-stroke engine. The bore and stroke measures 54 x 54.5 mm. From a practical standpoint, the 2023 125 SX tips the scales at 92.4 kg, carries a 7.20-litre fuel tank and offers a seat height of 958 mm. That's roughly 106.4 kg lighter than the average enduro / off-road motorcycle in our database. Scroll down for the complete 2023 KTM 125 SX spec sheet covering every technical detail from suspension travel to tyre sizes.

2023 125 SX - Pros & Cons

Strengths

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

Considerations

Tall seat height: The 958 mm seat height will challenge shorter riders - tiptoeing at low speeds is something to factor into your decision.
Modest fuel capacity: The 7.20-litre tank means more frequent fuel stops on longer rides, which is worth planning around on touring routes.
Chain final drive upkeep: Chain final drive needs regular cleaning, lubrication and tension checks to get full life out of the sprockets.

Wear Points & Servicing Notes

Fuelling & injector care

Fuelling comes from fuel injection. Systems like this are largely maintenance-free beyond keeping fuel quality decent and injectors clear - a fuel-system cleaner every service interval is cheap insurance.

Brake disc and pad wear

The Single disc front brake gives strong, progressive stopping power. Disc thickness and pad depth are worth checking at every tyre change, since worn pads can score the disc surface.

Suspension condition on used examples

Up front, the 125 SX runs WP XACT-USD, Ø 48 mm and WP XACT Monoshock with linkage at the rear. On a used example, check fork seals for weeping oil and test the rear linkage for play - seals are a relatively cheap fix but useful when negotiating price.

Final drive maintenance

Final drive is by chain - expect to clean and lube it every few hundred kilometres and check tension regularly; a neglected chain wears the sprockets faster than the chain itself.

Frame & chassis check

The frame is Central double-cradle-type 25CrMo4 steel - worth a visual check for corrosion or impact damage around the head-stock and swingarm pivot on any used example, since frame damage is far costlier to fix than any service item.

Low-speed handling

At just 92.4 kg, the 125 SX is light enough to manhandle easily at a standstill - one of the practical advantages of its class.

125 SX - Buying & Maintenance Guide

What to check before buying

When inspecting a used 2023 KTM 125 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 125 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 125 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.

Fuel system care

The 125 SX'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.

2023 KTM 125 SX - Frequently Asked Questions

What engine does the 2023 KTM 125 SX have?

The 2023 KTM 125 SX uses a Single cylinder, two-stroke engine with 124.8 cc of displacement.

How much does the 2023 KTM 125 SX weigh?

The 2023 KTM 125 SX weighs 92.4 kg. This is the manufacturer's dry figure.

What is the fuel tank capacity of the 2023 KTM 125 SX?

The 2023 KTM 125 SX has a 7.20-litre fuel tank. At around 5-6 litres per 100 km, that is roughly 120-144 km between stops.

Is the 2023 KTM 125 SX suitable for shorter riders?

The 2023 KTM 125 SX has a seat height of 958 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 2023 KTM 125 SX have?

The 2023 KTM 125 SX uses Single disc at the front and Single disc at the rear.

What tyre sizes does the 2023 KTM 125 SX use?

The front tyre size on the 2023 KTM 125 SX is 1.6-21.

What fuel system does the 2023 KTM 125 SX use?

The 2023 KTM 125 SX uses Injection, providing precise fuelling across the rev range and reliable cold-start behaviour.

KTM 125 SX Spec Evolution

The KTM 125 SX was produced across 21 model years (2003-2023). 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	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019	2020	2021	2022	2023
Wet Weight	-	-	-	-	-	-	-	-	104.0 kg / 229.3 lbs	292.1 kg / 643.9 lbs	-	112.0 kg / 246.9 lbs	-	-	-	-	-	-	-	-	-
Dry Weight	93.6 kg / 206.4 lbs	93.6 kg / 206.4 lbs	92.4 kg / 203.7 lbs	92.4 kg / 203.7 lbs	92.4 kg / 203.7 lbs	90.8 kg / 200.2 lbs	90.8 kg / 200.2 lbs	90.8 kg / 200.2 lbs	88.8 kg / 195.8 lbs	91.6 kg / 201.9 lbs	90.8 kg / 200.2 lbs	90.8 kg / 200.2 lbs	90.8 kg / 200.2 lbs	87.8 kg / 193.6 lbs	87.2 kg / 192.2 lbs	87.2 kg / 192.2 lbs	87.5 kg / 192.9 lbs	137 kg / 302.0 lbs	87.5 kg / 192.9 lbs	87.5 kg / 192.9 lbs	92.4 kg / 203.7 lbs
Engine Detail	-	-	-	-	-	-	-	-	-	Reed intake and exhaust control	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	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	Single cylinder, two-stroke
Seat Height	925 mm / 36.4 in.	925 mm / 36.4 in.	925 mm / 36.4 in.	925 mm / 36.4 in.	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.	992 mm / 39.1 in.	960 mm / 37.8 in.	960 mm / 37.8 in.	960 mm / 37.8 in.	950 mm / 37.4 in.	-	850 mm / 33.5 in.	950 mm / 37.4 in.	958 mm / 37.7 in.
Fuel Capacity	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 gallons	7.50 litres / 1.98 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	7.50 litres / 1.98 gallons	7.00 litres / 1.85 gallons	7.00 litres / 1.85 gallons	7.00 litres / 1.85 gallons	7.50 litres / 1.98 US gallons	-	7.50 litres / 1.98 US gallons	7.50 litres / 1.98 US gallons	7.20 litres / 1.90 US gallons
Stroke	2	2	2	2	2	2	2	-	-	-	-	-	-	-	-	-	-	-	-	-	2-stroke
Ground Clearance (mm)	390 mm	390 mm	390 mm	390 mm	390 mm	390 mm	390 mm	390 mm	385 mm	395 mm	395 mm	395 mm	395 mm	375 mm	375 mm	375 mm	375 mm	-	375 mm	375 mm	359 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

92.4 kg / 203.7 lbs

Fuel Capacity

7.20 litres / 1.90 US gallons

Full 2023 KTM 125 SX Specifications

Colours White/orange/grey

Ground Clearance (in.) 14.1 inches

Ground Clearance (mm) 359 mm

Seat Height 958 mm / 37.7 in.

Dry Weight 92.4 kg / 203.7 lbs

Fuel Capacity 7.20 litres / 1.90 US gallons

Power-to-Weight Ratio 0.1623 HP/kg

Stroke 2-stroke

Engine Type Single cylinder, two-stroke

Displacement (ci) 7.62 cubic inches

Displacement (cc) 124.8 cc

Bore x Stroke (in,) 2.1 x 2.1 inches

Bore x Stroke (mm) 54.0 x 54.5 mm

Fuel System Injection

Engine Lubrication Wet sump

Ignition Vitesco Technologies EMS

Starter Electric

Clutch Wet multi-disc DS clutch, Brembo hydraulics

Final Drive Chain (final drive)

Gearbox 6-speed

Primary Drive X-Ring 5/8 x 1/4´ chain

Frame Type Central double-cradle-type 25CrMo4 steel

Suspension - Front WP XACT-USD, Ø 48 mm

Suspension - Rear WP XACT Monoshock with linkage

Rake 26.1°

Wheel Travel - Front 310 mm / 12.2 in.

Wheel Travel - Rear 300 mm / 11.8 in.

Brakes - Front Single disc

Brakes - Rear Single disc

Tyres - Front 1.6-21

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