Racy-looking single is the first 125 on the market with an electronic quick-shifter.
Racy-looking single is the first 125 on the market with an electronic quick-shifter.

Aprilia RS4 125 a schoolboy's dream

By Staff reporter Time of article published Jul 9, 2012

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The Italians have always been good at building small sports bikes - one has only to think of the Garellis and Itoms of the 1960s - and the latest schoolboy dream machine from Aprilia continues that tradition.

Aprilia's first 125cc four-stroke sports bike - the RS4 125 - ticks all the high-tech boxes with electronic fuel injection, liquid cooling, a four-valve cylinder head with double overhead camshafts and a six-speed transmission.

The chassis uses all the know-how gained from Aprili's 345 Grand Prix wins and 45 World championships over 25 years, based on a die-cast aluminium spar frame with crossed reinforcing ribs for light weight and torsional stiffness.

Front suspension is entrusted to 41mm upside-down forks with black anodised sliders, while the rear monoshock is linked directly to the asymmetrical aluminium swing-arm.


Light six-spoked alloy wheels are shod with 130/70-17 front and 130/70-17 rear tubeless tyres, and braking is taken care of by a 300mm front disk and four-pot radial-mount calliper, and a 218mm rear disk with a straightforward single-piston sliding calliper.

Available as an extra-cost option, for the first time on a street-legal 125, is an electronic quick-shifter derived from the World Championship superbike, that allows the rider to change up at full tilt boogie without using the clutch or closing the throttle.

The Aprilia RS4 125 weighs only 120kg dry, but Aprilia has made it physically big enough to be considered a proper motorcycle rather than a toy, with a 14.5-litre fuel tank for decent range.


The usual comprehensive analogue rev-counter/liquid-crystal-for-everything-else instrument pod tells the rider everything he needs to know about the state of two-wheeled play, and a quick-release button allows the passenger seat to be removed, revealing a useful storage compartment. The pillion pad can also interchange with a tail fairing, making the bike into a stylish single-seater.

Experience suggests, however, that this is not a good idea for the school run, as a rucksack full of school books will scratch hell out of the paint on the tail fairing.

The Aprilia RS4 125 will be available at Aprilia dealers from the end of July. Pricing, as always, when they get here.


Engine:124.8cc liquid-cooled four-stroke single.

Bore x stroke:58 x 47mm.

Compression ratio:12.5:1.

Valvegear: DOHC with four overhead valves per cylinder.

Power:11.8 kW.

Induction: Electronic fuel-injection.

Ignition: Electronic with CDI capacity discharge.

Starting: Electric.

Clutch: Cable-operated multiplate wet clutch.

Transmission: Six-speed constant-mesh gearbox with final drive by chain.

Front Suspension:41mm inverted cartridge forks, non-adjustable.

Rear Suspension: Monoshock adjustable for preload.

Front brake:300mm disk with four-piston radial-mount monobloc calliper.

Rear brake:218mm disk with single-piston floating calliper.

Front tyre:100/80 - 17 tubeless.

Rear tyre:130/80 - 17 tubeless.


Seat height:820mm.

Dry weight:120kg.

Fuel tank:14.5 litres.

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