The RS 660 brought Aprilia back to the middleweight sport class with a 659 cc parallel twin, essentially the front half of the RSV4's V4, in an…
| MODEL | APRILIA RS 660 2021 |
| Year | 2021 |
| Engine Type | Four-stroke, forward-facing parallel twin, DOHC, 4 valves per cylinder |
| Displacement / Capacity | 659 cc / 40.2 cu in |
| Bore X Stroke | 81 x 63.93 mm |
| Compression Ratio | 13.5:1 |
| Cooling System | Liquid cooled, radiator and water-oil heat exchanger |
| Max Power | 73.5 kW / 100 hp @ 10500 rpm |
| Max Torque | 67 Nm / 6.83 kgm @ 8500 rpm |
| Ignition | — |
| Induction | Fuel injection, 2 x 48 mm throttle bodies, ride-by-wire |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | Wet sump |
| Gear Box | 6-speed, Aprilia Quick Shift (AQS) |
| Clutch | Wet, multi-plate, slipper |
| Final Drive | Chain, 17/43 |
| CHASSIS SPECS | |
| Frame | Aluminium double-beam frame, detachable rear subframe |
| Front Suspension | 41 mm Kayaba upside-down fork, 120 mm / 4.7 in travel |
| Rear Suspension | Aluminium asymmetric swingarm, monoshock adjustable for rebound and spring preload, 130 mm / 5.1 in travel |
| Front Brakes | 2 x 320 mm discs, Brembo radial 4-piston (32 mm) calipers, cornering multimap ABS |
| Rear Brakes | Single 220 mm disc, Brembo 2-piston (34 mm) caliper |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 815 mm / 32.0 in |
| Wheelbase | 1370 mm / 53.9 in |
| Ground Clearance | — |
| Dry Weight | 169 kg / 372.5 lbs |
| Wet Weight | 183 kg / 403.4 lbs |
| WHEEL SPECS | |
| Front Tyre | 120/70 ZR17 |
| Rear Tyre | 180/55 ZR17 (180/60 ZR17 alternative) |
| FUEL SYSTEM | |
| Fuel Capacity | 15 Litres / 3.9 US gal |
| Fuel Consumption | — |
| Top Speed | — |
The RS 660 brought Aprilia back to the middleweight sport class with a 659 cc parallel twin, essentially the front half of the RSV4's V4, in an aluminium double-beam frame that uses the engine as a stressed member. It aimed for usable road performance rather than outright track numbers, with a comfortable-for-the-class riding position, about 100 hp and the full APRC electronics suite, including cornering ABS and cruise control. A low dry weight of about 169 kg was one of its main selling points.
