Introduction

Aprilia - RX 50 (2003, ZD4TTB)

The Aprilia RX 50 with type code ZD4TTB was introduced in 2003 as part of the relaunched RX enduro series. It targets young beginners and off-road newcomers looking for a robust, lightweight motorcycle with a sporty appearance. Compared to sibling models, this version differs in equipment details and type approval – such as specific components, chassis codes, or market-specific homologation features. It is considered one of the most popular entry-level 50 ccm off-road bikes.

Model History

In 2003, Aprilia comprehensively updated its 50 ccm enduro range. The RX 50 (ZD4TTB) was released alongside type variants like ZD4TTA and ZD4TTC, all based on a new platform with improved ergonomics and a more modern design. Focus was on a youthful look, forgiving handling, and reliable technology. Depending on the market, equipment like lighting, exhaust, or gearing varied according to regulations. The RX 50 was also used for training purposes or youth racing in some countries.

Technical Details

Air-cooled single-cylinder two-stroke engine, 49 cm³ displacement, rotary valve intake and Dell’Orto carburetor. Open version output: approx. 7.0 hp at around 9,000 rpm. 6-speed manual gearbox with chain drive and kickstarter. CDI ignition, lubrication via premix or autolube depending on variant. Top speed (derestricted): ~75 km/h. Fuel tank: approx. 7 litres including reserve.

Chassis and Brakes

Tubular steel frame with detachable rear subframe for easy maintenance. Conventional telescopic fork at the front, rear mono shock with linkage and aluminium swingarm. Enduro wheels: 21″ front, 18″ rear with knobby tires. Disc brakes: 260 mm front, 180 mm rear; some versions came with braided brake lines as standard. Suspension setup aimed at light trail use and training environments.

Colour Variants

The RX 50 (ZD4TTB) was available in sporty colour schemes such as black-red, yellow-blue, or silver with contrasting RX graphics. Depending on model year and market, wheel colour, decals and plastic parts like the front fairing or side panels varied. Popular accessories included handguards, performance exhaust systems, reinforced chains or different sprockets for street or trail use.