2023 · Supersport · Buyer's Guide
Light Weight, Real Bite
The Extrema is the sharp end of the RS 660 line: a lightweight, track-leaning special edition built around a 659 cc parallel twin making 100 hp and 49 lb-ft, carried by a chassis that comes in at 397 lb (180 kg) wet. An SC-Project exhaust is standard equipment here, not a shopping-list item. What makes it credible in this class is that the electronics match the intent. Cornering ABS, traction control, wheelie control, ride modes and the bidirectional Aprilia Quick Shift (AQS) all arrive from the factory, alongside suspension that is adjustable front and rear. That is a genuine supersport package rather than a styling exercise.
On the road it rewards accuracy more than bravery. There is enough power to be properly quick on a good stretch and not so much that you spend the whole ride managing it, which is why it suits riders sharpening technique on canyon roads, Appalachian twisties, or the occasional track day. Cruise control, a TFT dash and a riding position that doesn't fold you in half keep it usable on the days in between. The honest caveat: some engines have shown oil seeping or consumption traced back to gaskets and seals, and it looks less common on 2023 production. Inspect the bottom end on any used bike.
Spec sheets don't ride bikes, but they set the baseline.
| Power | 100 hp (74 kW) @ 10,500 rpm |
|---|---|
| Torque | 49 lb-ft (67 Nm) @ 8,500 rpm |
| Displacement | 659 cc |
| Engine | Parallel twin |
| Cooling | Liquid-cooled |
| Gearbox | 6-speed |
| Final drive | Chain |
| Fork | Upside-down (USD) |
| Front brake | 320 mm |
| Front tire | 120/70-17 |
| Rear tire | 180/55-17 |
| Wheelbase | 54.1 in (1375 mm) |
| Seat height | 32.3 in (820 mm) |
| Wet weight | 397 lb (180 kg) |
| Fuel capacity | 4.0 gal (15 L) |
Equipment check
Chassis
Connectivity
Drivetrain
Lighting
Safety
The first thing you register swinging a leg over is how small it feels around you. The 32.3 in (820 mm) seat drops you into the bike rather than perching you on it, the clip-ons sit high enough that your wrists aren't carrying your weight, and the tank gives your knees something honest to lock onto. The SC-Project pipe hands the twin a hard, flat bark as the revs climb and keeps it civil at a cruise. Vibration is there without ever going numb; you feel the pulse through the pegs more than the bars. At real road pace it sits light and awake underneath you, moving the instant you look through a corner. The TFT is readable in hard California sun, which matters more than it sounds.
Potential oil leaks (less frequent on 2023 models)
Oil seeping or consumption has been noted on some engines, often traced to gasket or seal issues; appears less prevalent on later production.
Where this Aprilia RS 660 Extrema pulls ahead of — or falls behind — its rivals on the numbers, and the typical bike in its class on character.
Power
Torque
Displacement
Wet weight
Seat height
Forget spec-sheet bragging. Here's who the RS 660 Extrema is actually built for.
This is the bike Angeles Crest was built for. Light, precise, and happy to be ridden hard once you clear the traffic, without leaving you cooked by the time you roll back down.
Made for Angeles Crest Highway · Coronado Trail / US 191 · Highway 1 / Big Sur
It won't win the straight, but it will teach you apexes. Adjustable suspension at both ends and a full rider-aid package give you real room to develop a setup and your technique.
Made for Barber Motorsports Park · WeatherTech Raceway Laguna Seca · Circuit of the Americas
Tight, repeating corners are exactly its habitat. The low weight and the feel coming through the front let you work on precision instead of hauling a heavy bike from turn to turn.
Made for Back of the Dragon · Blue Ridge Parkway · Cherohala Skyway
If this one isn't quite the fit, these are the bikes worth riding back-to-back against it.
Any price note compares both bikes at the same age — the youngest age both have on the used market — against this Aprilia RS 660 Extrema. “cheaper/pricier” is what that bike costs second-hand, not how worn it is.
