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2021 Aprilia RS 660 first ride review

Oct 26, 2020

Word has it that several years ago during a discussion about future models, someone at Aprilia asked what a motorcycle powered by half of an RSV4 V-four would look like. 

Well, you’re looking at it, and I just spent 200 miles on it in the hills above Santa Barbara, California.

riding the Aprilia RS 660
The RS 660 is an entirely new take on what a lightweight twin can be. Photo by Kevin Wing.

The new RS 660 is fun, flickable, and definitely fast enough to keep you grinning. It has a compact parallel-twin engine that pumps out a claimed 100 horsepower and 49 foot-pounds of torque (at the crank) via hot-rod tuning, and it comes wrapped in an aluminum twin-spar frame and is laden with up-spec components and every electronic feature you can imagine. All told, the RS is said to weigh a scant 403 pounds with its four-gallon tank topped off, and it’ll be in dealerships in December with an MSRP of $11,300.

A whole new take on the lightweight twin

Don’t let the RSV4 DNA or racy looks mislead you. Contrary to common perceptions, the RS 660 is not another race bike with lights. It is designed to hold its own at the occasional track day, certainly, but first and foremost it’s intended to excel on the winding back roads, highways, and even the city streets of the real world.

Historically, the 650ish cc class has been budget-friendly and mild-mannered – great for beginners and pragmatic riders, but not terribly exciting or sophisticated. Meanwhile, 600 cc supersports have evolved solely for and within the confines of racing, rendering them too aggressive (in terms of riding position, suspension setup, and engine character) for everyday use. 

In addition to Apex Black, the RS 660 is available in Lava Red (foreground) and Acid Gold (background), the latter at a $200 premium. Aprilia photo.

There’s never really been a middle ground, even though plenty of riders (myself included) have hopped up SV650s and MT-07s with GSX-R or YZF-R6 and R1 suspension and brakes in an attempt to forge one.

Finally, someone has reimagined the lightweight twins category in a way that many of us have always wished. Aprilia wiped the slate clean and drew a bike with the approachable nature and versatility we all love about lightweight twins, and combined it with a bit more purebred performance and higher-end componentry. On top of that, the RS 660 offers a level of technology that not even the 600s can compete with. 

Hit me with the hardware details

Aprilia went with a parallel twin with a 270-degree crank for the sake of size, design freedom, and character. There’s some truth to the “half an RSV4” thing, though Aprilia didn’t just saw a cylinder bank off the 1100. That would only leave us with 539 cc, which wouldn’t be competitive. Instead, Aprilia utilized the same 81.0 mm bore as the 1100, but the pistons slide through 63.9 mm of stroke for a total displacement of 659 cc. The resulting package is compact, offering advantages in terms of weight, engine placement, exhaust routing, and rider ergonomics. The 100 horsepower Aprilia claims is measured at the crank, which means there's likely 85 or so ponies being put down at the rear wheel. 

Aprilia’s new twin is said to make 100 horsepower at 10,500 and 49 foot-pounds of torque at 8,500 rpm. More impressively, the engine makes 80 percent of maximum torque from just 4,000 rpm. Aprilia illustration.

The two-cylinder layout also offers a broad spread of accessible power, with a demeanor similar to that of a V-twin, thanks to the uneven firing order of the crank layout. If you haven’t ridden a 270-degree twin yet, it’s worlds apart from the bland, vibey feel of the traditional 180-degree arrangement used in a Kawasaki Ninja 300 or 650. 

The RSV4 trickle-down extends to the shape of the combustion chambers and ports, which are key aspects of a high-performance engine. As is a high compression ratio, and the 660 steps up with a steep 13.5:1 figure. Yes, you’ll need to run premium gas. Pistons squeezing stuff that hard have to deal with a lot of heat, so oil jets squirt the underside of the domes and there’s an oil/water heat exchanger to keep the lube cool. None of this is new tech, but it’s rare in this segment.

From the sky-high 13.5:1 compression ratio to the slipper clutch, this new 659 cc engine is packed with trickle-down tech from the RSV4. Aprilia illustration.

Same goes for the electronics. There’s a TFT dash, bi-directional quickshifter, IMU-informed ABS with cornering functionality and front-only track mode, wheelie control, multi-level traction control, adjustable engine braking, emergency brake function (the blinkers flash when you slam on the brakes), five programmable ride modes, a gas gauge, gear-position indicator, cruise control, lithium-ion battery, LED cornering lights, and probably more that I’m not remembering. Expected equipment on a modern, $25,000 halo bike, sure, but genuinely surprising on an $11,300 daily rider. 

LED headlights feature perimeter running lights and IMU-informed cornering lights. Photo by Kevin Wing.

It’s a lot of tech, but thanks to a well laid out dash and a new (somewhat chunky) switch cluster on the left bar, everything is easy to navigate and adjust. On top of that, the features are effective in practice, not just nifty in theory. 

Chassis design is one of the Noale factory’s specialties, and the RS 660 carries on the tradition. Broad cast-aluminum frame spars bolt to a separate headstock, which acts as the passageway for intake air. The engine serves as a structural component, supporting a long, asymmetric gull-wing swingarm via lugs at the rear of the crankcase. Rather than being polished to a mirror finish as is customary, the frame and swingarm are painted silver. It’s a small concession, given how well equipped the bike is. 

The RS 660 in Apex Black. Yup, the bike has two different-colored wheels. Yeah, it annoys me, too. So does the way the silver paint on the swingarm got scuffed by my right boot heel. Owners will want to apply a protective decal over that area stat. Aprilia photo.

Then, there’s that claimed 403-pound, fully fueled weight. Lightness makes everything better (well, except stability in crosswinds), and Yamaha’s MT-07 is the only bike in the segment that compares. Other models — even 600 supersports — are 15 or more pounds heavier on account of their larger (dimensionally) engines. The RS’s svelte physique and reasonable MSRP are the result of careful component design that includes one-piece cast rearsets, a one-piece, welded exhaust system, plastic dash and fairing supports, clip-ons that bolt directly to the top triple clamp (as on the KTM RC390), and a linkageless shock. 

The shock, like the 41 mm inverted fork, are made by Kayaba and offer spring preload and rebound damping. Compatriots Brembo and Pirelli supply the brake hardware and rolling stock, respectively, and the rear tire is a full-size 180/55R-17.  

You can't turn ABS off, but turning it down to Level 1 means you can lock (or loft) the rear wheel. Photo by Kevin Wing.

It’s supposed to be comfortable? But it looks like a sport bike! 

It sure does, and a damn attractive one at that. The triple headlight and layered fairing bear a clear resemblance to the latest RSV4 1100 superbike, but the ergonomics are nowhere near as committed. Aprilia says the rider triangle splits the difference between a Yamaha YZF-R6 and a Kawasaki Ninja 650. In other words, it’s sporty enough to feel appropriate while attacking apexes, but not so hunched over that it’s intolerable after several hours in the saddle. Likewise, the suspension is compliant enough to smooth out rough roads, while still providing enough support and stroke control to encourage assertive throttle, brake, and steering inputs. These are difficult balances to strike, and the RS 660 does it well.

The RS 660 is designed to slot in between basic budget bikes and super-focused 600 cc supersports. Aprilia illustration.

The grips are wide set and sit about an inch above the steering pivot so your wrists don’t carry much weight, and you don’t have to lift your boots nearly as high as you’d expect to find the footpegs. The seat is flat and well padded, and even if it sits 32.3 inches above the pavement the bike is quite narrow between your legs, so the effective seat height feels lower. That, combined with the bike’s light weight and excellent balance, should make the RS welcoming for newer or shorter riders. 

The RS 660 fits me, at five feet, 10 inches, perfectly. Taller riders in at the press launch (including my six-foot, two-inch friend Abhi Eswarappa from Bike-urious) said it worked for them, as well. 

Despite race bike looks, Aprilia's new RS is at home in an urban environment. For perspective, that's a five-foot, 10-inch rider. Photo by Kevin Wing.

My test bike (VIN 000003!) was fitted with a prototype seat cowl, but the RS comes with a passenger pad that is actually large enough to be called a seat. The exhaust routing keeps hot bits away from your body, and the under-engine exit leaves plenty of room for extended passenger footpeg brackets, so the person on the back can actually feel secure. 

Removing the passenger seat reveals a flat platform ideal for a top box or bungee straps and cargo. What a clever, useful idea. Photo by Ari Henning.

Come on already, what’s it like to ride? 

In a word? Excellent. I don’t want to sound excessively enthusiastic, but the fact is the bike is strong in myriad ways and doesn’t have any major weaknesses — at least none that I was able to uncover with a 200-mile street ride. And 200 miles is about how many miles the odometer showed when I turned the RS 660’s key for the first time and the vivid TFT dash blinked on.

Pressing the starter button sets the crank spinning into a pleasant, lumpy idle. The nasally honk from the staggered intake funnels in the airbox is more prominent than the noise coming from the muffler when you blip the throttle, but overall the RS has a satisfying and distinct sound.

It's not just the TFT that's beautiful; the whole cockpit is attractive and tidy. Photo by Kevin Wing.

With a slick transmission and light, progressive clutch, it’s easy to get the RS moving, and once underway the rumbling sensation of the engine at low rpm feels every bit like that of a V-twin. Throttle response is smooth regardless of which engine mode you select, with none of the pronounced off/on abruptness I’ve come to expect from modern, highly regulated fueling.

The RS has the kind of tight turning radius that makes parking-lot U-turns and urban maneuverability easy. It’s also incredibly well balanced at low speeds, so I practiced not putting my feet down, "Daily Rider" style, as we threaded through downtown Santa Barbara amid wafting fog and early morning joggers.

Whacking the throttle open while rolling onto the freeway sends a shudder through the footpegs and seat, and as revs rise beyond 7,000 rpm vibrations begin to blur the mirrors. Thankfully, sixth gear is quite tall and nets 70 mph at 5,000 rpm, with the engine loping along smoothly and 60-plus mpg showing on the instant readout. Top gear is long enough that a downshift is advised if you need a squirt of speed for passing. Acceleration is forceful in the lower gears and power picks up noticeably above 7,500 rpm, where the engine seems to rev up faster toward the 11,500-rpm redline. 

Quickshifters are a fun and functional way to make a bike feel sportier. The RS's linkage can be switched to GP (reverse) shifting and still retain the quickshifter function. Photo by Kevin Wing.

As mentioned earlier, the rider triangle is reasonable and the seat is supportive, so droning along the highway isn’t a test of one’s endurance. Cruise control relieves your right wrist of responsibility, and even if the arced windscreen isn’t tall enough to fully route wind around your helmet and torso, the well refined bodywork leaves you sitting in smooth airflow. The distinctive layered fairing design is said to be especially aerodynamic and serves to divert engine heat and provide a stabilizing effect at speed, similar to what the wings on the RSV4 do. 

Can it corner? 

On the familiar, wonderfully twisty mountain roads above Santa Barbara, I was finally able to experience the RS 660 as the sport bike everyone presumed it to be.

And it’s a freakin’ blast. The handling is light, the bike changes direction with just a nudge of the bars, and there’s no need for body language to drag it down to full lean. I appreciate that Aprilia used a similar tank shape on the RS as on the RSV4 (and Tuono), because the broad, curved flanks allow you to easily anchor yourself to the bike with your legs.

Rider's perspective of the RS fulfilling its rennsport destiny. Note the 12 or so millimeters of fork extending above the triple clamp. That'll provide crucial ride-height adjustment for track riders. Photo by Ari Henning.

The new engine that was so tractable and polite around town and relaxed on the freeway wakes up when you goose it, though the robust midrange grunt means that there’s really no need to spin it to redline. It won’t loft the front wheel on command or break the sound barrier like an RSV4, but you can easily clutch up a wheelie in first or second gear and the bike accelerates quickly toward a likely top speed of 140 mph. 

When it comes time to slow down, the brakes are overkill — just the way I like them. Not too much bite but big-time power and solid feedback, backed up by an ABS system that’s widely adjustable. Level 1 is front-only and permits lurid endos and rear-wheel slides, while Level 3 prioritizes safety and stability and incorporates a cornering function that takes into account lean angle to tailor the skid response accordingly. I like that you can dial the system up on rainy rides or turn it down to the point that it’s a last-ditch safety net when you want to hoon around. You can’t turn ABS all the way off, but given how lenient Level 1 is, there’s no need to. 

Even with a wide, 180-section rear tire, handling is responsive enough that there's no need to pull the bike down to full lean with body language. Photo by Kevin Wing.

And then there’s the eight-level TC (that can be turned off), which many commenters have scoffed at on a 100-horsepower bike. Sure, if the pavement is clean and dry you’re not likely to break the rear tire free, but a wet manhole cover or crosswalk can be slick enough to pitch a scooter sideways. TC isn’t always about accelerating off an apex with your knee dragging on the ground. 

Of course it wheelies! Though the long swingarm, forward engine placement, and non-soggy shock make the RS more eager to rocket forward than lift the front wheel. Photo by Kevin Wing.

Speaking of things dragging, during the 100 or so miles of spirited canyon carving we did I burnished the Pirelli Rosso Corsa II rear tire all the way to the shoulders, yet never once dragged the footpeg feelers. Given the legroom, that’s impressive. 

At the end of the day, I rode as hard and fast as is sensible on the street and never found the bike’s limits. And despite how much I abused the throttle, I still averaged a calculated 42 mpg (the computer average was an optimistic 48) for a real-world range of 160 miles. I’d say 200 miles is easily attainable with a more restrained wrist. 

Where does it fit in? (i.e., is it better than a YZF-R6?!?) 

Oddly (in my opinion), a common question leading up to the 660’s launch was whether it was better than a Yamaha YZF-R6. Since 600 cc supersports are, unfortunately, still an aspirational choice for newer riders, and since the internet has no limit on article word count, I’ll entertain the comparison. But let’s discuss the more obvious competitors first. 

A key aspect of the RS 660's versatility is its balanced riding position. Aprilia says it splits the difference between a Kawasaki Ninja 650 and a Yamaha YZF-R6. Aprilia illustration.

And by that I mean the $7,500 Suzuki SV650, $7,600 Yamaha MT-07, $8,800 Kawasaki Ninja 650, and $9,700 Honda CBR650R. The only leg up those bikes have on the RS 660 is a varying degree of savings. Simply put, there’s nothing in the familiar crop of bikes that can hold a candle to the RS 660. 

The real comparison, then, are bikes like Triumph’s 765 cc, $10,800 Street Triple R, KTM’s 799 cc, $10,700 790 Duke, and perhaps Ducati’s 937 cc, $12,995 Supersport. Comparing the Aprilia to the Ducati is a stretch in terms of specification, if not approach, and the KTM and Triumph might not be getting cross shopped since they don’t have full fairings, which is a key style element for many American buyers. Especially among younger, emotionally driven riders. 

Mission control for the majority of the Aprilia's many features and settings. Mercifully, the menu system is pretty straightforward. Photo by Kevin Wing.

Which brings me, begrudgingly, to the 600 cc supersport class. The RS 660 can’t compete in terms of outright power or track performance and is only cheaper than the $12,200 YZF-R6, but it’s lighter and more feature-rich than anything in the 600 cc category, and as far as real-world practicality, it clobbers crotch rockets like an 11-year-old wrecks a piñata. 

If I may step onto my soap box for a moment and speak to those who still measure a machine’s worth solely by its maximum output, please know that while [insert any 600 cc supersport here] may make marginally more power, it’s not until the engine has been given time to spin up to 13,000 rpm. Meanwhile, the RS 660 (and all the other lightweight twins and middleweight nakeds out there, for that matter) is tuned for a broader spread of power so it’s much easier to keep in the sweet spot, which ultimately makes for a much more enjoyable, practical, and even faster riding experience.

I won’t even get started about ergonomics. 

Final thoughts: The significance of the Aprilia RS 660 

The RS 660 is a major direction change, not just for Aprilia, but for all of motorcycling. Engine size, price, and technology have ballooned as a trio, but now we’re seeing top-tier tech applied to a displacement category — and at a price point — that actually makes sense.

What we’re left with is an incredibly functional bike that’s as suitable for commuting as it is for tearing up a canyon road. The RS 660 is an excellent upgrade for someone moving on from a 400-class bike, a welcome respite for those suffering from 600 cc PTSD, and a great match for anyone who appreciates functionality and performance in a lightweight package.  

The split fairing is unique and attractive, especially since it’s not interrupted by blinkers. Those are integrated into the mirrors here in the United States and integrated into the headlight on the European model. Aprilia photo.

This isn’t just a tangent for Aprilia, it’s a whole new trajectory. The 660 engine will spawn a number of new models, including a Tuono naked bike that’s said to arrive in spring of 2021 and a Tuareg adventure bike by the end of next year. 

Maybe the thing I’m most excited about is the 660 platform’s potential to legitimize the lightweight twins category the same way the KTM RC 390 and Kawasaki Ninja 400 did the small-bike class. With its cache and performance, the RS 660 and its kin could alter perceptions of the class and help steer the market toward a new breed of exciting, mid-displacement bikes. 

2021 Aprilia RS 660

Price (MSRP) $11,299
Engine 659 cc, liquid-cooled, eight-valve, parallel twin
final drive
six-speed, chain
Claimed horsepower 100.0 horsepower @ 10,500 rpm
Claimed torque 49.0 foot-pounds @ 8,500 rpm
Frame Aluminum twin-spar
Front suspension Kayaba 41 mm fork adjustable for spring preload and rebound damping; 4.7 inches of travel
Rear suspension Kayaba shock adjustable for spring preload and rebound damping; 5.1 inches of travel
Front brake Brembo four-piston calipers,  320 mm discs with ABS
Rear brake Brembo two-piston caliper, 220 mm disc with ABS
Rake, trail 24.1 degrees, 4.1 inches
Wheelbase 53.9 inches
Seat height 32.3 inches
Fuel capacity 4.0 gallons
Tires Pirelli Diablo Rosso II, 120/70R-17 front, 180/55R-17 rear
Claimed weight 403 pounds
Available December 2020
Warranty 24 months, unlimited miles
More info