The new Aprilia RS 660 and the Tuono 660 made their global debut in late 2020 and was soon confirmed to make their way to India. Both models have been developed from the ground up and mark a new chapter for the Italian bike maker. The models use a 659 cc, parallel-twin, liquid-cooled engine with a 270-degree firing order. The engine has been derived from the front two cylinders of the V4 engine of the Aprilia RSV4 1100. The motor develops 99 bhp at 10,500 rpm and 67 Nm of peak torque at 8500 rpm on the RS 660. It's tuned for 95 bhp at 10,500 rpm and 67 Nm at 8500 rpm on the Tuono. The power mill is paired with a 6-speed gearbox.

Both bikes use Kayaba 41 mm USD front forks and an asymmetrically-mounted rear monoshock. Braking power comes from 320 mm dual discs at the front and a 220 mm rotor at the rear. The RS 660 and the Tuono 660 get a 15-litre fuel tank and tip the scales at 183 kg. The bikes use cast aluminium wheels wrapped in Pirelli Diablo Rosso Corsa tyres.