Motocross Bikes
2018KTM 125 SX
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The 2018 KTM 125 SX is a lightweight, entry-level motocross bike designed for young riders and beginners entering competitive racing. It combines nimble handling, excellent suspension travel, and aggressive styling in a compact package that rewards technique over brute power. Best known for its reliability and approachable performance, the 125 SX remains the ideal gateway into serious off-road competition.
- Capacity
- 124.8 ccm
- Engine
- Single, two-stroke
- Gearbox
- 6-speed
- Dry weight
- 87.2 kg
- Seat height
- 960 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
- 0.1720 HP/kg (dry)
- Bore x stroke
- 54.0 x 54.5 mm
- Cooling system
- Liquid
- Fuel system
- Carburettor
- Starting
- Kick
- Ignition
- Kokusan EMS
- Lubrication system
- Wet sump
Transmission
- Gearbox
- 6-speed
- Transmission type
- Manual
- Final drive
- Chain
- Clutch
- Multi-plate clutch, Brembo hydraulics
Dimensions & weight
- Wheelbase
- 1485 mm
- Seat height
- 960 mm
- Dry weight
- 87.2 kg
- Fuel capacity
- 7.00 litres
- Ground clearance
- 375 mm
Chassis & suspension
- Frame
- Chrome-molybdenum steel central-tube frame
- Front suspension
- WP-USD, AER 48, Ø 48 mm
- Rear suspension
- WP shock absorber with linkage
- Front wheel travel
- 300 mm
- Rear wheel travel
- 300 mm
- Rake (fork angle)
- 26.5°
- Trail
- 120 mm
Brakes & wheels
- Front brakes
- Single disc. Brake calipers on floating bearings
- Front brakes diameter
- 260 mm
- Rear brakes
- Single disc. Brake calipers on floating bearings
- Rear brakes diameter
- 220 mm
- Front tyre
- 110-17
- Rear tyre
- 150-17
Other
- Color options
- Orange/white/black
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 | 2018 | 2020 | 2027 |
|---|---|---|---|---|---|---|
| Capacity | 125 cc | 125 cc | 125 cc | 125 cc | 125 cc | 125 cc |
| Dry weight | 94 kg | 91 kg | 91 kg | 87 kg | 88 kg | 92 kg |
| Seat height | 925 mm | 985 mm | 992 mm | 960 mm | 950 mm | 958 mm |
| Fuel capacity | 7.5 L | 8 L | 7.5 L | 7 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 2018 KTM 125 SX has a Capacity of 124.8 ccm (7.62 cubic inches).
What engine power does the KTM 125 SX have?
The 2018 KTM 125 SX has a Power of 15.0 HP (11.0 kW).
How many gears does the KTM 125 SX have?
The 2018 KTM 125 SX has a Gearbox of 6-speed.
How much does the KTM 125 SX weigh?
The 2018 KTM 125 SX has a Dry weight of 87.2 kg (192.2 pounds).
Shop this bike
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The 2018 KTM 125 SX motorcycle is a high-performance, lightweight bike that is perfect for off-road racing and trail riding. With its powerful 125cc engine and top-of-the-line suspension, this motorcycle offers exceptional handling and agility. The bike's sleek design and cutting-edge technology make it a top choice for riders who want a competitive edge on the track. Whether you're a seasoned racer or a beginner, the KTM 125 SX will deliver an adrenaline-pumping ride every time.
The 2018 KTM 125 SX motorcycle is a top contender in the 125cc off-road bike category. Its impressive power, precise handling, and advanced features make it a standout choice for riders seeking top performance. Whether you're hitting the trails or competing in races, this bike offers the perfect combination of power and agility. With its sleek design and superior engineering, it's no wonder the KTM 125 SX is a favorite among off-road enthusiasts.
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