Engineered by KTM for the enduro - offroad motorcycle segment, the 2012 KTM 125 SX relies on a 124.8 cc (7.6 cu in) liquid-cooled single cylinder, two-stroke powerplant. 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 91.6 kg (202 lbs) dry. Rider ergonomics and chassis geometry center around a 992 mm (39.1 in) seat height — reflecting a long-travel chassis stance that favors ground clearance and off-pavement control, combined with a 1,480 mm (58.3 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
992 mm (39.1 in)
Engine
Displacement124.8 ccm (7.62 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsReed intake and exhaust control
Bore x Stroke54.0 x 54.5 mm (2.1 x 2.1 inches)
Fuel SystemCarburettor. Keihin PWK 38S AG
IgnitionContactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan
LubricationMixture oil lubrication 1:40
CoolingLiquid
Transmission
Gearbox6-speed
Final DriveChain (final drive)
ClutchWet mDouble disk clutch / hydraulically operated
Driveline13:50
Chassis
Frame TypeCentral tube frame made of chrome molybdenum steel tubing
Rake26.5°
Front SuspensionWPÂ Suspension
Front Travel300 mm (11.8 inches)
Rear SuspensionWPÂ Suspension
Rear Travel330 mm (13.0 inches)
Wheelbase1480 mm (58.3 inches)
Ground Clearance395 mm (15.6 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 Weight91.6 kg (201.9 pounds)
Seat Height992 mm (39.1 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.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
