Introduction

Aprilia - RS 50 (1999, ZD4TSB)

The Aprilia RS 50 with the type designation ZD4TSB from the year 1999 is a variant of the sporty RS series in the 50 cc segment. It combines dynamic styling with proven engineering, targeting riders looking for a sporty design with everyday usability in the small-capacity category.

Model History

In the late 1990s, Aprilia introduced several versions of the RS 50 to meet regional requirements and homologation standards. The ZD4TSB version is one of these adaptations, marked by specific graphics or minor equipment changes. The technical foundation remained largely unchanged across these editions.

Technical Specifications

The RS 50 (ZD4TSB) is powered by a liquid-cooled single-cylinder two-stroke engine with a displacement of approximately 49.9 cm³. Comparable RS models from the same era delivered about 4.7 kW (6.4 hp). Power is transmitted through a 6-speed manual gearbox and a chain-driven final drive. A carburettor handles fuel supply, as was standard at the time.

Chassis and Brakes

The chassis features an aluminium bridge frame designed for stiffness and agile handling. At the front, either a telescopic or an upside-down fork is used, while a monoshock supports the rear. Braking is handled by a large front disc and a smaller rear disc. Typical tyre sizes for this model are **100/80‑17 at the front** and **130/70‑17 at the rear**.

Dimensions & Weight

The seat height is around **820 mm**, which is typical for 50 cc sport bikes. The wet weight is generally about **132 kg**. The fuel tank holds approximately **14.5 litres**, as standard in the RS series. The bike measures about **1,965 mm** in length, **720 mm** in width, and has a wheelbase of around **1,355 mm**.

Colour Variants

The ZD4TSB version was likely available in classic RS liveries with race-inspired graphics, including contrasting colour accents, striping and logos to emphasise the sporty character. Technically, this version was largely identical to other RS 50 variants – differences were mostly in appearance and optional features.