At the heart of the 2008 KTM 50 SX Junior minibike, cross motorcycle, KTM pairs a 49 cc (3 cu in) liquid-cooled single cylinder, two-stroke architecture with road-focused gearing. 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 Junior measures 37.6 kg (83 lbs) dry. Rider ergonomics and chassis geometry center around a 585 mm (23 in) seat height — giving shorter riders and urban commuters confident flat-foot reach at traffic stops, combined with a 910 mm (35.8 in) wheelbase engineered for quick, flickable steering geometry. The 1.8-liter (0.5 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's KTM archive, this model family spans 4 indexed model years from 2006 to 2009, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Standover Height
585 mm (23 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 PHVA 14 DS
IgnitionSeletra analogue
LubricationMixture lubrication 1:60
CoolingLiquid
Transmission
GearboxAutomatic
ClutchCentrifugal clutch (adjustable)
Performance
ExhaustAluminium
Chassis
Frame TypeCentral double-cradle-type frame
Rake24.0°
Trail90 mm (3.5 inches)
Front SuspensionMarzocchi
Front Travel120 mm (4.7 inches)
Rear SuspensionWP monoshock
Rear Travel125 mm (4.9 inches)
Wheelbase910 mm (35.8 inches)
Ground Clearance220 mm (8.7 inches)
Wheels & Brakes
Front Tyre2.50-10
Rear Tyre2.75-10
Front BrakesSingle disc. Bremo
Front Brake Ø160 mm (6.3 inches)
Rear BrakesExpanding brake (drum brake). Bremo
Rear Brake Ø90 mm (3.5 inches)
Dimensions & Weight
Dry Weight37.6 kg (82.9 pounds)
Seat Height585 mm (23.0 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.
