The RS4 50 replaced the long-running RS 50 as Aprilia's entry-level two-stroke sportbike, wearing bodywork modelled closely on the RSV4 superbike…
| MODEL | APRILIA RS4 50 2010 - 2011 |
| Year | 2010 - 2011 |
| Engine Type | Single cylinder, two-stroke, reed valve |
| Displacement / Capacity | 49.9 cc / 3.04 cu in |
| Bore X Stroke | 39.9 x 40.0 mm / 1.57 x 1.57 in |
| Compression Ratio | 11.5:1 |
| Cooling System | Liquid cooled |
| Max Power | 2.0 kW / 2.7 hp @ 5250 rpm |
| Max Torque | 3.5 Nm / 2.6 lb-ft @ 5500 rpm |
| Ignition | Electronic CDI |
| Induction | Dell'Orto PHVA 17.5 carburettor, reed valve |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | Separate oil mixing (automatic mixer) |
| Gear Box | 6-speed |
| Clutch | Wet multi-plate, oil bath |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Twin-spar aluminium frame |
| Front Suspension | 41 mm upside-down fork, 110 mm / 4.3 in wheel travel |
| Rear Suspension | Asymmetric swingarm with monoshock, 130 mm / 5.1 in wheel travel |
| Front Brakes | Single 300 mm stainless steel disc, radial 4-piston caliper |
| Rear Brakes | Single 218 mm stainless steel disc, single 25 mm piston caliper |
| DIMENSION SPECS | |
| Overall Length | 1953 mm / 76.9 in |
| Overall Width | 740 mm / 29.1 in |
| Overall Height | 1138 mm / 44.8 in |
| Seat Height | 820 mm / 32.3 in |
| Wheelbase | 1350 mm / 53.1 in |
| Ground Clearance | — |
| Dry Weight | 122 kg / 269 lbs |
| Wet Weight | 132 kg / 291 lbs |
| WHEEL SPECS | |
| Front Tyre | 110/80-17 |
| Rear Tyre | 130/70-17 |
| FUEL SYSTEM | |
| Fuel Capacity | 14.5 Litres / 3.8 US gal |
| Fuel Consumption | — |
| Top Speed | 45 km/h / 28 mph |
The RS4 50 replaced the long-running RS 50 as Aprilia's entry-level two-stroke sportbike, wearing bodywork modelled closely on the RSV4 superbike with its triple headlight and short tail. Underneath it gained a twin-spar aluminium frame, a 41 mm upside-down fork and a six-speed gearbox behind the reed-valve single. Aimed at 16-year-old learners, it was sold restricted for AM licences, with a removable cowl that turns the dual seat into a solo seat.
