Built around KTM's cross - motocross motorcycle platform, the 2003 KTM 125 SX features a 124.8 cc (7.6 cu in) liquid-cooled single cylinder, two-stroke configuration. Internal engine geometry specifies a bore and stroke of 54.0 x 54.5 mm (2.1 x 2.1 inches).
On the scales, the 125 SX measures 93.6 kg (206 lbs) dry. Rider ergonomics and chassis geometry center around a 925 mm (36.4 in) seat height — reflecting a long-travel chassis stance that favors ground clearance and off-pavement control, combined with a 1,461 mm (57.5 in) wheelbase engineered for balanced agility and highway composure. The 7.5-liter (2 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's KTM archive, this model family spans 23 indexed model years from 2003 to 2025, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Standover Height
925 mm (36.4 in)
Engine
Displacement124.8 ccm (7.62 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsSingle cylinder, two-stroke
Bore x Stroke54.0 x 54.5 mm (2.1 x 2.1 inches)
Fuel SystemCarburettor
CoolingLiquid
Transmission
Gearbox5-speed
Final DriveChain (final drive)
Chassis
Front Travel300 mm (11.8 inches)
Rear Travel335 mm (13.2 inches)
Wheelbase1461 mm (57.5 inches)
Ground Clearance390 mm (15.4 inches)
Wheels & Brakes
Front Tyre80/100-21
Rear Tyre100/90-19
Front BrakesSingle disc
Front Brake Ø260 mm (10.2 inches)
Rear BrakesSingle disc
Rear Brake Ø220 mm (8.7 inches)
Dimensions & Weight
Dry Weight93.6 kg (206.4 pounds)
Seat Height925 mm (36.4 inches) If adjustable, lowest setting.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
