At the heart of the 2021 Ktm 150 SX cross - motocross motorcycle, Ktm relies on a 144 cc (8.8 cu in) liquid-cooled single cylinder, two-stroke powerplant. Internal engine geometry specifies a bore and stroke of 58.0 x 54.5 mm (2.3 x 2.1 inches).
On the scales, the 150 SX measures 87.5 kg (193 lbs) dry. Rider ergonomics and chassis geometry center around a 850 mm (33.5 in) seat height — resulting in a taller command-style riding posture suited to medium-to-tall inseams, combined with a 1,485 mm (58.5 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 15 indexed model years from 2009 to 2025, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Standover Height
850 mm (33.5 in)
Engine
Displacement144.0 ccm (8.79 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsReed intake.
Bore x Stroke58.0 x 54.5 mm (2.3 x 2.1 inches)
Fuel SystemCarburettor. Mikuni TMX
IgnitionKokusan EMS
CoolingLiquid
Transmission
Gearbox6-speed
Final DriveChain (final drive)
ClutchMulti-plate clutch, Brembo hydraulics
Driveline14:50. Primary drive: 23:73.
Chassis
Frame Type25CrMo4 steel central-tube
Rake26.1°
Front SuspensionWP XACT-USD, Ø 48 mm
Front Travel310 mm (12.2 inches)
Rear SuspensionWP XACT Monoshock with linkage
Rear Travel300 mm (11.8 inches)
Wheelbase1485 mm (58.5 inches)
Ground Clearance375 mm (14.8 inches)
Wheels & Brakes
Front BrakesSingle disc. Four-piston calipers.
Front Brake Ø260 mm (10.2 inches)
Rear BrakesSingle disc. Two-piston calipers.
Rear Brake Ø220 mm (8.7 inches)
WheelsCNC machined hubs. Excel rims. Wire spoked.
Dimensions & Weight
Dry Weight87.5 kg (192.9 pounds)
Seat Height850 mm (33.5 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.
