2021 Aprilia RS 660 Technical Review

Staying true to these COVID times, our tech preview of the 2021 Aprilia RS 660 took place not at a crowded EICMA-style get-together, but rather via a Zoom call that virtually linked Italian engineers to Stateside journalists. Also joining the convo was famed designer Miguel Galluzzi, who broadcasted live from the brand’s Advanced Design Center in Pasadena, near the famed Art Center College of Design where he studied.

Editor’s Note: We recently test rode the RS 660 during the official North American press introduction. Find out more in the 2021 Aprilia RS 660 MC Commute Review.

Of course we’ve already previewed, road tested, and even commuted in the $11,299 middleweight. But here’s a detailed lowdown on some of the advances that help Aprilia’s latest stand out from its competitors.

Before getting into the nitty-gritty, let’s consider the weak points Aprilia claims are rampant in the 600 supersport segment. For starters, the Noale, Italy, manufacturer critiques most middleweight performance bikes as either too committed to be comfortable, too revvy to be usable, or too pricey to be accessible. Aprilia’s team thus focused on designing a motorcycle that won’t exhaust its riders after a canyon run and doesn’t need to rev to the stratosphere to perform, yet is affordable enough for budget-minded bike shoppers.

“The RS stands for RennSport,” Aprilia spokesperson Shane Pacillo explains, referring to a hat tip to Aprilia’s mini race replica RS 50 and RS 125 two-strokes that stoked the go-fast spirit of young European riders. Boasting a claimed best-in-class wet weight of 403 pounds, the new RS 660′s efficient structure comes in the form of a twin-spar aluminum frame that acts as a load-bearing element, and an aluminum swingarm. The subchassis is 16mm narrower than the RSV4′s, allowing easier boot-to-pavement access to bolster confidence in newer riders. Cornering clearance is aided by footpegs positioned 18.2mm more inboard compared to the RSV4. An underslung exhaust weighing 13.6 pounds aids the RS 660′s mass centralization efforts, as well as an alloy rear subframe (4.3 pounds) and cast aluminum front and rear wheels (7.8 and 11.6 pounds, respectively). “Weight containment was our greatest challenge,” Aprilia head engineer Piero Soatti admits.

The RS 660 is powered by a new parallel-twin engine that’s the first Aprilia mill to meet stringent Euro 5 requirements. Producing 100 hp at 10,500 rpm and 49 pound-feet of torque at 8,500 rpm, the 658.8cc twin is more flexible than it sounds: Although it revs to 11,500 rpm, 80 percent of its torque comes from 4,000 rpm, and by the time 6,250 rpm rolls around you’re tapping into 90 percent of available twist. As speed accumulates, the RS 660′s aerodynamics are managed by a double-layer fairing designed to extract hot air from the engine, create a boundary layer of nonturbulent air, and reduce drag.

Aiding the engine’s intangibles, its 270-degree crank helps lend it an exhaust note that sounds surprisingly like a V-twin. A few other elements were borrowed from the RSV4′s powerplant including output-optimized manifolds, a four-bar gasoline injection system, a CFD-designed combustion chamber, and a 48mm ride-by-wire throttle.

It wouldn’t be a tech talk without the topic of electronics, and central to that point is the new upgraded Marelli 11 MP engine control unit which has been beefed up to handle the engine’s complex responsibilities. By expanding from 80 to 114 pins, upping the clock frequency from 50 MHz to 200 MHz, and bumping the flash memory from 1 Mb to 4 Mb, the computer is able to handle more than just ignition and timing parameters. Connected to myriad components via CAN BUS, the ECU now manages headlamp functionality for the first time, running elements like the automatic DRL and beam switch, emergency braking (which flashes both indicators during hard braking), and so-called bending lights, which anticipate corners by aiming the headlamps to either side.

A six-axis accelerometer/gyroscope manages a suite of electronic aids, including customizable settings like eight-level traction control, three-level cornering ABS, and single-level wheelie control. Also managed via ride modes are three-level engine-braking and engine management settings. Added bonus: The RS 660 comes standard with cruise control, making it the rare sportbike that’s also ready for soul-deadening freeway slogs. Conspiring along with the long-distance friendly tech is a surprisingly comfortable saddle. The multitude of adjustable settings can be manipulated via the APRC buttons on the left switch gear when the bike is stationary; quick selection of preset riding modes can be toggled while on the go. All info is revealed on a bright full-color TFT display.

While there’s plenty of tech that surprises and delights in a segment usually reserved for full-blown race replicas (see: Yamaha YZF-R6), there’s also enough thoughtful engineering to make the 2021 Aprilia RS 660 feel as ergonomically agreeable as more middle-of-the-road offerings like the Honda CBR650R and Kawasaki Ninja 650. More crucially, it helps prepare Aprilia for the future, according to Piaggio’s US President and CEO Mario Di Maria. “It’s not just a new motorcycle for us,” he says, “it’s a new platform where new motorcycles will be developed.”