2021 Aprilia SR 50 Factory Technical Analysis & Specification Breakdown
At the heart of the 2021 Aprilia SR 50 Factory scooter motorcycle, Aprilia utilizes a 49 cc (3 cu in) liquid-cooled single cylinder, two-stroke layout. In factory specification, peak output is rated at 4 HP (2.9 kW) at 7,000 rpm while maximum torque reaches 4 Nm (3 lb-ft) at 6,500 rpm, transferring power to the rear wheel through a automatic gearbox and belt final drive. Internal engine geometry specifies a bore and stroke of 40.0 x 39.3 mm (1.6 x 1.5 inches) with a 12.1:1 compression ratio.
On the scales, the SR 50 Factory measures 107 kg (236 lbs) dry. Rider ergonomics and chassis geometry center around a 795 mm (31.3 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,260 mm (49.6 in) wheelbase engineered for quick, flickable steering geometry. The 7.6-liter (2 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 45 km/h (28 mph).
Within MotoLibrary's Aprilia archive, this model family spans 2 indexed model years from 2014 to 2021, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Power Band Window
6,500–7,000 rpm
Standover Height
795 mm (31.3 in)
Engine
Displacement49.0 ccm (2.99 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsHi-Per 2 Pro engine
Power4.0 HP (2.9 kW)) @ 7000 RPM
Torque4.0 Nm (0.4 kgf-m or 3.0 ft.lbs) @ 6500 RPM
Compression12.1:1
Bore x Stroke40.0 x 39.3 mm (1.6 x 1.5 inches)
Fuel SystemCarburettor
IgnitionCDI
LubricationSeparate mixing with mechanical oil pump
CoolingLiquid
Transmission
GearboxAutomatic
Final DriveBelt (final drive)
ClutchAutomatic centrifugal dry clutch
DrivelineGears in oil bath final drive
Performance
Top Speed45.0 km/h (28.0 mph)
Emission DetailsEuro 4
Chassis
Frame TypeSplit single cradle frame in high tensile strength steel tube
Front SuspensionTelescopic hydraulic fork
Front Travel90 mm (3.5 inches)
Rear SuspensionEngine unit acting as swingarm. Monoshock.
Rear Travel70 mm (2.8 inches)
Wheelbase1260 mm (49.6 inches)
Wheels & Brakes
Front Tyre130/60-13
Rear Tyre130/60-13
Front BrakesSingle disc. 2 opposing pistons
Front Brake Ø190 mm (7.5 inches)
Rear BrakesSingle disc. 2 opposing pistons
Rear Brake Ø190 mm (7.5 inches)
WheelsFive spoke, light alloy wheels
Dimensions & Weight
Dry Weight107.0 kg (235.9 pounds)
Power/Weight0.0376 HP/kg
Seat Height795 mm (31.3 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.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Torque
Torque is useful for judging real-world pull, especially for touring, commuting and loaded riding.
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.
