Built around KTM's minibike, cross motorcycle platform, the 2009 KTM 50 SX relies on a 49 cc (3 cu in) liquid-cooled single cylinder, two-stroke powerplant. Internal engine geometry specifies a bore and stroke of 39.5 x 40.0 mm (1.6 x 1.6 inches) with a 12.5:1 compression ratio.
On the scales, the 50 SX measures 39.8 kg (88 lbs) dry. Rider ergonomics and chassis geometry center around a 684 mm (26.9 in) seat height — giving shorter riders and urban commuters confident flat-foot reach at traffic stops, combined with a 1,030 mm (40.6 in) wheelbase engineered for quick, flickable steering geometry. The 2.3-liter (0.6 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's KTM archive, this model family spans 19 indexed model years from 2006 to 2025, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Standover Height
684 mm (26.9 in)
Engine
Displacement49.0 ccm (2.99 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsSingle cylinder, two-stroke
Compression12.5:1
Bore x Stroke39.5 x 40.0 mm (1.6 x 1.6 inches)
Fuel SystemCarburettor. Dell´Orto PHBG 19 BS
IgnitionSeletra analogue
LubricationMixture lubrication 1:60
CoolingLiquid
Transmission
GearboxAutomatic
Final DriveChain (final drive)
ClutchCentrifugal clutch
Performance
ExhaustAluminium
Chassis
Frame TypeDouble grinded central double-cradle-type frame. Steel subframe.
Rake24.0°
Trail90 mm (3.5 inches)
Front SuspensionMarzocchi, 32 mm
Front Travel185 mm (7.3 inches)
Rear SuspensionWP monoshock
Rear Travel185 mm (7.3 inches)
Wheelbase1030 mm (40.6 inches)
Ground Clearance255 mm (10.0 inches)
Wheels & Brakes
Front Tyre60/100-12
Rear Tyre2.75-10
Front BrakesSingle disc. Bremo
Front Brake Ø160 mm (6.3 inches)
Rear BrakesSingle disc. Bremo
Rear Brake Ø140 mm (5.5 inches)
Dimensions & Weight
Dry Weight39.8 kg (87.7 pounds)
Seat Height684 mm (26.9 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.
