Aprilia RS 125 Service Manual (2002)

Aprilia built its reputation in lightweight road sport motorcycles by transferring ideas from Grand Prix racing into machines aimed at young riders. The RS 125 name appeared in the early 1990s, and Piaggio Group's official RS history describes its 1992 debut as an early example of the close exchange between Aprilia's racing and road-bike programmes. Aprilia's own historical archive also records the RS 125 Extrema and RS 125 Sport Pro in 1993, establishing the model as the road-going centrepiece of the company's 125 cc sporting range.

By the 2002 era, the RS 125 had developed into a mature two-stroke lightweight sportbike built around a 124.82 cm³ liquid-cooled single-cylinder engine with reed-valve induction and separate automatic oil injection. Factory specifications list a 54 × 54.5 mm bore and stroke, 12.5:1 compression, a six-speed gearbox and Dell'Orto PHBH 28 carburetion. Full-power versions added Aprilia's RAVE exhaust-valve system, which altered exhaust-port timing with engine speed to broaden the useful power delivery, while restricted 11 kW versions allowed the platform to meet different licensing and homologation requirements.

The chassis was designed with the same race-replica emphasis. A stamped-and-cast twin-beam frame carried 17-inch light-alloy wheels, hydraulic suspension and large disc brakes, including a 320 mm front disc. The 2002 workshop data gives a 1,345 mm wheelbase, 805 mm seat height and a ready-to-start weight of 139 kg including fuel and fluids. Clip-on controls, full bodywork and a compact riding position reinforced the visual and dynamic link with Aprilia's small-capacity racing machinery rather than with conventional commuter motorcycles.

The model's competition association was especially visible in 2002. Aprilia Racing's official palmarès records that Aprilia won both the 125 cc riders' and manufacturers' World Championships that season, with Arnaud Vincent taking the riders' title. The road-going RS 125 was not the Grand Prix machine itself, but that racing environment shaped the model's identity and helped make Aprilia's 125 sport bikes an important entry point into the brand.

The two-stroke RS 125 remained a long-running part of Aprilia's range before a major technical break in 2011, when the company introduced the four-stroke RS4 125. Piaggio Group's official RS4 history states that more than 100,000 two-stroke RS 125s had been produced and sold in more than 30 countries since 1993 before the four-stroke successor arrived. This listing is based specifically on the November 2002 factory workshop publication; although it contains references to earlier variants, it does not establish blanket 1998-2005 applicability. Related documentation is grouped in the Aprilia RS 125 manual category.