The Twins Cup might get a rude awakening this year when a few Aprilia RS 660’s rock up for the green light.
By Rennie Scaysbrook | Photos by Cali Photography
Turns three, four, five, six and seven at Buttonwillow Raceway in California are an excellent bunch of bends to test a machine’s handling.
The long, cambered-then-off-cambered right of turn two is followed by a short straight and some heavy braking for the right of three, then it’s a snap left-right-downhill right-uphill right and over the wheelie jump on the exit of Grapevine (turn seven). You can tell when a bike works by how quickly it gets through that last section of turns, and this is just one area the Aprilia RS 660 shows its considerable teeth.
Fitted with ultra-sticky Pirelli Superbike SC1 slicks, Aprilia’s first mid-size dynamo is absolutely on rails, allowing me to brake extremely late into turn three and pass a series of bikes twice its capacity when the anchors are heaved on. Having just had the stock suspension fetted by my Pikes Peak International Hill Climb Crew Chief Jeremy Toye, the braking stability of the RS 660 chassis is absolutely superb, even if the actual power offered by the radially mounted Brembo four-piston monobloc calipers and the Brembo radial master-cylinder are not as impressive on track as it is on the street.
The lack of overall weight compared to a bigger bike, and the skinny feel of the chassis gives loads of confidence to the rider while cranked over. Its turn speed is huge, partly due to the 5.5-inch rear wheel compared to the 6-inch units more commonly found on sportbikes. You can throw the RS around and it just keeps coming back for more, and when watching someone like Rocco Landers pumping the RS 660 around Buttonwillow, you know the bike has potential exceeding that of many a rider.
The wheelbase is rather compact at 53.9 inches, and with a bike weighing 403 pounds wet (claimed) and matched to a 24.1° rake, it’s enough to help you max out your turn speed but keep a degree of stability at your fingers. There were slight changes between the final production RS 660 chassis and that which we saw debut at EICMA in 2018 in prototype form, with the main frame rails narrowed and the engine mounts moved closer to the steering head, helping tilt the motor forward and putting more weight on the front for better braking and cornering stability.
Part of what makes the RS 660 so good in the corners, especially the tight switchbacks of Buttonwillow, is the Engine Brake Control (EBC), part of the Aprilia Performance Ride Control electronics suite and the six-axis Inertial Measurement Unit.
These electronics are even more advanced than the RSV4 1100 Factory’s and allow the rider to dial in just the right amount of engine brake to pull the machine into the apex of the corner. You can go from almost no engine braking, so you can ride it like a two-stroke with massive corner-entry speed to full four-stroke. Then you’ve got the beautiful Aprilia Traction Control (ATC) system, variable to eight different levels, so you can hammer the throttle on corner exits with all the confidence afforded to machines in the superbike class. This is a considerable advantage over any other machine currently in the Twins Cup category.
Then you’ve got that engine. What can you say other than this is simply the new benchmark in the Twins Cup? With about 85 horsepower at the tire (depending on the dyno operator), the Aprilia simply walks away from its competitors and isn’t that far off what a stock, four-cylinder supersport machine produces. You’ve got five variable engine levels with the APRC system, but you’ll want to put it into the Challenge mode, where you get the closest 1-1 connection with the throttle to what you’ll get at the tire.
You’ll want to make sure you change gear on the sweet-action quickshifter before you crash into the harsh rev-limiter at 11,500 rpm, but by then you’ve run past where all the acceleration is. Keep the RS surfing between 8-10,000 rpm, and you’re met with constant drive and torque to pull you from one corner to the next. It truly is an addictive little engine.
Aprilia has given you a bit of a blank canvas with the RS 660. It’s a compact ride, and those taller than six feet will want to extend the seat unit back when they convert it into a track/race bike with aftermarket bodywork. Even though the handlebars are mounted atop the triple clamp, there’s plenty of space to fit proper clip-ons because the RSV4-esque side air intakes are not actually intakes at all, just extra bodywork. The intake is at the front of the nosecone, so fitting track-specific handlebars will not be an issue so long as you change the top triple clamp.
And you’ll want to get a good set of rearset footpegs to get your legs a bit higher and further back, tilting you forward to help load the front more under braking. These are standard racebike mods and will turn the RS 660 from a sporty commuter into a proper race weapon. However, you won’t have to make anywhere near the changes required by the two Japanese rivals in the Twins Cup to make a competitive track bike.
The MotoAmerica Twins Cup is changing, and once this thing starts romping away with race wins this year, it may turn into an Aprilia Cup in much the same way Kawasaki has done with the Junior Cup and their Ninja 400.
Hopefully, the success of the RS 660, both on track and in the showroom, will see a revamped push from the major manufacturers in the Supertwin class, because the real-world performance of the Aprilia is absolutely undeniable and is exactly what the sportbike world needs right now. Until then, get ready to see the Aprilia RS 660 smoke all before it.CN
2021 Aprilia RS 660 Specifications
| MSRP: | $11,299 |
| Engine: | 4-stroke, Aprilia parallel twin, forward facing |
| Cooling System: | Liquid-cooled with water-oil radiator and heat exchanger |
| Displacement: | 659cc |
| Valvetrain: | DOHC, 8 valves |
| Bore x stroke: | 81 x 63.9mm |
| Fuel injection: | EFI, full ride-by-wire 48mm throttle bodies |
| Compression ratio: | 13.5:1 |
| Power (claimed): | 100 hp at 10,500 rpm |
| Torque (claimed): | 49.4 lb-ft at 8500 rpm |
| Exhaust: | 2-into-1 |
| Transmission: | 6-speed w/Aprilia Quickshifter |
| Clutch: | Multi-plate wet clutch w/mechanical slip system |
| Electronics: | 6-axis inertial platform, APRC package containing ATC (Aprilia Traction Control), AWC (Aprilia Wheelie Control), AEB (Aprilia Engine Brake), AEM (Aprilia Engine maps) and ACC, (Aprilia Cruise Control); five Riding modes (Road and Track, three fixed and two customizable) |
| Chassis: | Aluminum dual-beam chassis with removable seat support subframe |
| Front suspension: | Kayaba 41mm fork, aluminum radial caliper mounting bracket, fully adjustable |
| Rear suspension: | Aluminum asymmetric swingarm, fully adjustable |
| Front-wheel travel: | 4.72 in. |
| Rear-wheel travel: | 5.12 in. |
| Front brake: | Brembo radial calipers 4-piston; cornering ABS |
| Rear brake: | 220mm disc, 2 piston Brembo caliper; cornering ABS |
| Front tire: | 120/70 ZR17 in. |
| Rear tire: | 180/55 ZR17 in. |
| Rake: | 24.1° |
| Wheelbase: | 53.9 in. |
| Seat height: | 32.3 in. |
| Fuel capacity: | 3.96 gal. |
| Weight (wet, claimed): | 403 lbs. |
Click here to read the 2021 Aprilia RS 660 Review in the Cycle News Digital Edition Magazine.
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