Aprilia RS 125 2004 — Specifications

Arnaud Vincent secured his 125cc World Championship title on a machine derived from what you could buy at your Aprilia dealership. This isn't a fabricated marketing claim to sell a dream; it's a reality that quite well summarizes what the Aprilia RS 125 version 2004 is: a competition motorcycle with civil registration.

The Aprilia RS 125 engine is a 125 cc two-stroke single-cylinder, with a square bore of 54 x 54.5 mm, and a compression ratio of 12.5:1. In its restricted version to comply with legislation, it requires intensive use of the six-speed gearbox to remain within the useful power range. Unleashed, and many owners eventually take that step, the 2T Aprilia RS 125 develops approximately 28.6 hp at 10,500 rpm for a torque of 19 Nm at 10,250 rpm. Relative to its displacement, this is a power density that would make many higher-category four-strokes blush. The maximum speed of the Aprilia RS 125 is around 155 km/h, a figure that makes sense on a track, much less so on a peripheral boulevard.

The perimeter aluminum frame, the 40 mm inverted fork with 120 mm of travel, the rear mono-shock absorber calibrated in the same spirit: everything here is sized to exploit this potential. The front brake, a 320 mm disc pinched by a four-piston caliper, is noticeably oversized for a 125. Tires in 110/70-17 and 150/60-17 complete a geometry that inspires confidence as soon as the road becomes winding. At 139 kg fully fueled, the power-to-weight ratio is that of a track bike disguised as a homologated machine.

Facing the Cagiva Mito, its direct rival in the segment of sporty 125s of the time, the RS more explicitly plays the GP lineage card. The Aprilia RS 125 fairing adopts the aesthetic codes of the RS 250 competition bike, itself dominant in the World Championship. This is no coincidence: Noale has built a consistent range from the bottom up, and the 125 is the logical foundation. For those looking for an Aprilia RS 125 used today, whether on the classifieds or with a specialist, the price remains sustained precisely because this consistency is rare.

This isn't a motorcycle for everyone. The 805 mm seat height, the 14 liters of tank capacity, the performance usable only at high RPM: all indicate a specific profile, that of the young rider who wants to progress on the track, not that of a beginner looking for a versatile mount for their daily commutes. Aprilia RS 125 parts are still found, Aprilia RS 125 decoration kits too, which testifies to an active community around these machines. But buying an RS 125 for the city is like entrusting a surgeon's scalpel to someone who needs a kitchen knife.