Introduction

Aprilia - RS 50 HP/LM (1993–1994, ZD4MM)

The Aprilia RS 50 HP/LM with the type code ZD4MM was one of the very first models in Aprilia’s sporty RS series and was produced between 1993 and 1994. It combined an aggressive sport design with capable 50 cc technology, setting new standards for sporty small-capacity motorcycles in this class.
With features such as an aluminium bridge frame and disc brakes front and rear, it was well ahead of its time.

Model history

The RS 50 HP/LM was conceived as an entry into the world of supersport motorcycles – its design and concept closely mirroring larger models like the RS 125.
Introduced in 1993, it quickly established itself as a benchmark among sporty 50 cc motorcycles. The “HP” stood for “High Performance”, while “LM” referred to a light-alloy version – though this designation was never officially standardised.
The model was built until 1994, before being replaced by updated versions.

Technical details

The RS 50 HP/LM is powered by an air- or water-cooled single-cylinder two-stroke engine (depending on specification) with around 49 cc displacement – typically a Minarelli AM3/AM4 unit.
Power output: approx. 1.5 kW in restricted form, up to 6.5 hp derestricted.
Its 6-speed gearbox and sporty gearing made the RS 50 HP/LM ideal for learning manual shifting and sporty riding.
A carburettor engine with easy maintenance, aimed at young riders with AM/A1 licences.

Chassis and brakes

Aluminium bridge frame, telescopic fork at the front and monoshock at the rear.
Disc brakes front and rear (approx. 240 mm front, 220 mm rear), hydraulically operated.
Sporty 17-inch tyres with sizes around 90/80-17 front and 110/80-17 rear.
The chassis was firmly tuned, enabling precise handling – exceptional for this capacity class at the time.

Design and equipment

Strong visual cues from the RS 125 – twin-headlight look, full fairing and low clip-on handlebars.
Combination instrument cluster with rev counter, analogue speedometer and indicator lights.
Fuel tank capacity approx. 11 litres – sufficient even for longer trips within the 50 cc segment.
Typically fitted with a sporty single or stepped seat.

Colour variants

Available in classic racing colours such as silver, red, black or blue – often with contrasting Aprilia logos.
No officially documented special editions for this early series, but some factory-applied alternative graphics existed.
Many bikes were individually styled or received performance upgrades such as exhaust systems or larger carburettors.