Motocross Bikes
2027KTM 125 SX
33 fields on record
The KTM 125 SX continues for 2027 as KTM's smallest-displacement two-stroke motocross racer, powered by a 124.8cc single-cylinder two-stroke engine with a 39mm Keihin throttle body, through a 6-speed gearbox and Brembo-actuated wet clutch. It shares its chromoly steel frame, WP XACT air fork, and WP XACT monoshock with the rest of the SX two-stroke lineup, at a 958mm seat height and light overall weight built for explosive, high-revving performance. It remains a pure competition machine for intermediate-to-expert motocross riders.
- Capacity
- 124.8 ccm
- Engine
- Single, two-stroke
- Gearbox
- 6-speed
- Dry weight
- 92.4 kg
- Seat height
- 958 mm
- Power
- 15.0 HP (11.0 kW)
Other years
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2025
2026
2027
How it rides
Editorial estimate from the spec sheet - not lab tested- Best for
- Built purely for closed-course motocross racing, it excels at jumps, berms, and rapid direction changes on dirt tracks rather than any street use.
- Built for
- Light, explosive, and razor-sharp in handling, it rewards aggressive riding with a peaky two-stroke power band and minimal weight to manage.
- Not ideal for
- It is not suitable for commuting, highway travel, passengers, or riders seeking comfort, storage, or a forgiving low-end power delivery.
Scores are derived from the spec sheet using the same model across every bike, so they compare like for like.
Will it fit you?
Worked out in your browser - nothing is sent to usEngine
- Capacity
- 124.8 ccm
- Power
- 15.0 HP (11.0 kW)
- Engine type
- Single, two-stroke
- Power/weight ratio
- 0.1623 HP/kg (dry)
- Bore x stroke
- 54.0 x 54.5 mm
- Cooling system
- Liquid
- Fuel system
- Injection
- Starting
- Electric
- Ignition
- Vitesco Technologies EMS
- Lubrication system
- Wet sump
Transmission
- Gearbox
- 6-speed
- Transmission type
- Manual
- Final drive
- Chain
- Clutch
- Wet multi-disc DS clutch, Brembo hydraulics
Dimensions & weight
- Wheelbase
- 1493 mm
- Seat height
- 958 mm
- Dry weight
- 92.4 kg
- Fuel capacity
- 7.20 litres
- Ground clearance
- 359 mm
Chassis & suspension
- Frame
- Central double-cradle-type 25CrMo4 steel
- Front suspension
- WP XACT-USD (AER), Ø 48 mm
- Rear suspension
- WP XACT Monoshock with linkage
- Front wheel travel
- 310 mm
- Rear wheel travel
- 300 mm
- Rake (fork angle)
- 26.1°
- Trail
- 120 mm
Brakes & wheels
- Front brakes
- Disc brake
- Front brakes diameter
- 260 mm
- Rear brakes
- Disc brake
- Rear brakes diameter
- 220 mm
- Front tyre
- 110-17
- Rear tyre
- 150-17
Specs last verified against published sources: .
Compiled from manufacturer documentation and user contributions, corrected on an ongoing basis. Spotted something wrong? Tell us.
What changed, year to year
Differences highlighted| Specification | 2003 | 2009 | 2015 | 2020 | 2027 |
|---|---|---|---|---|---|
| Capacity | 125 cc | 125 cc | 125 cc | 125 cc | 125 cc |
| Dry weight | 94 kg | 91 kg | 91 kg | 88 kg | 92 kg |
| Seat height | 925 mm | 985 mm | 992 mm | 950 mm | 958 mm |
| Fuel capacity | 7.5 L | 8 L | 7.5 L | 7.5 L | 7.2 L |
Illustrative - generated automatically by diffing the year records already on file, not a manufacturer-published changelog.
Rider Reviews
Common questions
What is the engine size of the KTM 125 SX?
The 2027 KTM 125 SX has a Capacity of 124.8 ccm (7.62 cubic inches).
What engine power does the KTM 125 SX have?
The 2027 KTM 125 SX has a Power of 15.0 HP (11.0 kW).
How many gears does the KTM 125 SX have?
The 2027 KTM 125 SX has a Gearbox of 6-speed.
How much does the KTM 125 SX weigh?
The 2027 KTM 125 SX has a Dry weight of 92.4 kg (203.7 pounds).
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