Engineered by Aprilia for the sport motorcycle segment, the 2018 Aprilia RS4 50 pairs a 49.9 cc (3 cu in) liquid-cooled single cylinder, two-stroke architecture with road-focused gearing. Internal engine geometry specifies a bore and stroke of 39.9 x 39.9 mm (1.6 x 1.6 inches) with a 11.5:1 compression ratio.
Rider ergonomics and chassis geometry center around a 820 mm (32.3 in) seat height — resulting in a taller command-style riding posture suited to medium-to-tall inseams, combined with a 1,350 mm (53.1 in) wheelbase engineered for quick, flickable steering geometry. The 14.5-liter (3.8 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's Aprilia archive, this model family spans 7 indexed model years from 2011 to 2018, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
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.
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.
