Motocross Bikes
2003KTM 125 SX
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The 2003 KTM 125 SX is a lightweight motocross machine designed for amateur and intermediate riders seeking aggressive off-road performance. Known for its responsive 125cc two-stroke engine and nimble handling, this bike excels in sand and technical terrain. The compact chassis and 93.6kg weight make it ideal for developing riding skills and enjoying competitive racing.
- Capacity
- 124.8 ccm
- Engine
- Single, two-stroke
- Gearbox
- 5-speed
- Dry weight
- 93.6 kg
- Seat height
- 925 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
- 0.1603 HP/kg (dry)
- Bore x stroke
- 54.0 x 54.5 mm
- Cooling system
- Liquid
- Fuel system
- Carburettor
- Starting
- Kick
- Ignition
- Kokusan digital 2K-1
- Lubrication system
- Mixture oil lubrication 1:40
Transmission
- Gearbox
- 5-speed
- Transmission type
- Manual
- Final drive
- Chain
- Clutch
- Wet multi-disc clutch, operated hydraulically
Dimensions & weight
- Wheelbase
- 1461 mm
- Seat height
- 925 mm
- Dry weight
- 93.6 kg
- Fuel capacity
- 7.50 litres
- Ground clearance
- 390 mm
Chassis & suspension
- Frame
- Chromium molybdenum
- Front suspension
- WP-USD 48/26 MA/PA
- Rear suspension
- WP-PDS-DA shock absorber
- Front wheel travel
- 300 mm
- Rear wheel travel
- 335 mm
- Rake (fork angle)
- 24.0°
- Trail
- 63 mm
Brakes & wheels
- Front brakes
- Single disc
- Front brakes diameter
- 260 mm
- Rear brakes
- Single disc
- Rear brakes diameter
- 220 mm
- Front tyre
- 80/100-21
- Rear tyre
- 100/90-19
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 2003 KTM 125 SX has a Capacity of 124.8 ccm (7.62 cubic inches).
What engine power does the KTM 125 SX have?
The 2003 KTM 125 SX has a Power of 15.0 HP (11.0 kW).
How many gears does the KTM 125 SX have?
The 2003 KTM 125 SX has a Gearbox of 5-speed.
How much does the KTM 125 SX weigh?
The 2003 KTM 125 SX has a Dry weight of 93.6 kg (206.4 pounds).
Shop this bike
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The 2003 KTM 125 SX is a lightweight and powerful motocross bike that delivers an exhilarating riding experience. With its 125cc engine and top-notch suspension, this bike is designed for maximum agility and control on the track. The sleek and aggressive design of the 2003 KTM 125 SX is sure to turn heads, while the responsive handling will impress even the most experienced riders. Whether you're a seasoned racer or a novice rider, this bike is sure to deliver the thrills and performance you're looking for.
Overall, the 2003 KTM 125 SX is a fantastic choice for anyone looking for a high-performance motocross bike. Its lightweight and agile design make it perfect for tackling tight corners and challenging jumps, while the powerful engine ensures plenty of speed and acceleration. Whether you're hitting the track for a race or just enjoying a day of off-road riding, the 2003 KTM 125 SX is a reliable and impressive choice that won't disappoint. With its sleek design and top-notch performance, this bike is a standout in the world of motocross.
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