Engineered by KTM for the cross - motocross motorcycle segment, the 2004 KTM 125 SX pairs a 124.8 cc (7.6 cu in) liquid-cooled single cylinder, two-stroke architecture with road-focused gearing. 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 1,471 mm (57.9 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
Frame TypeChromium molybdenum
Rake24.0°
Trail63 mm (2.5 inches)
Front SuspensionWP-USD 48/26 MA/PA
Rear SuspensionWP-PDS-DA shock absorber
Wheelbase1471 mm (57.9 inches)
Ground Clearance390 mm (15.4 inches)
Wheels & Brakes
Front BrakesSingle disc
Front Brake Ø216 mm (8.5 inches)
Rear BrakesSingle disc
Rear Brake Ø260 mm (10.2 inches)
Dimensions & Weight
Dry Weight93.6 kg (206.4 pounds)
Seat Height925 mm (36.4 inches) If adjustable, lowest setting.
Alt. Seat Height675 mm (26.6 inches) If adjustable, highest 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.
