Aprilia RS4 125 Specs

About the Aprilia RS4 125

The RS4 125 was a significant technical shift for Aprilia, replacing the two-stroke RS 125 with a modern, liquid-cooled 125cc four-stroke, four-valve engine with electronic fuel injection. While it moved away from the "smoke and revs" of the past, the RS4 brought a new level of mechanical sophistication to the A1 class, including the first available quick-shifter (AQS) in the 125cc segment. This allowed for seamless upshifts without closing the throttle, a technology taken directly from the RSV4 superbike. The chassis is a high-spec perimeter frame made of die-cast aluminum, providing a level of rigidity and feedback that remains the benchmark for small-displacement sportbikes. It features 41mm upside-down forks and a 300mm front disc with a four-piston radial caliper. This database provides the technical dimensions and performance figures for the RS4 125, including its fuel economy and dry weight. For the modern learner, the RS4 125 offers the look and feel of a world-champion superbike with the reliability and efficiency of a four-stroke engine.