2008 Aprilia SL 750 Shiver Twin Road Test
The Aprilia Shiver is Aprilia’s first middleweight sportbike, a product of its plant in Noale, Italy. This factory has already served as the birthplace of the Tuono and RSV models, and many scooters, but in the past Aprilia had been buying its motors from Rotax. Now that it has become part of the Piaggio Group, Aprilia is building some of its own motors, including the Shiver’s liquid-cooled, 90-degree V-twin. With a bore and stroke of 92 x 56.4mm, this big-bore/short-stroke design indicates an engine that makes its power and peak torque at relatively high rpm; its dual overhead cams actuate its four valves per cylinder through a combination of gears and chains. This modular design also enables Aprilia to use this platform as the basis for creating motors in various displacement categories in the future.
The Aprilia SL 750 is a tight package, its muscles densely packed within its steel trellis frame, led by a dual-parabola headlight above that 43mm male-slider fork and followed by an aluminum-alloy swingarm with reinforcing truss. The Shiver’s sporting orientation is obvious from its engine, frame, brakes and styling. Still, its raised, tubular handlebar and high seat do not subject the rider to the extreme leaned-forward, cramped seating position so common to many street-ready racers. Climb aboard and the Shiver presents an orange-and-silver tank (the only color scheme available in the United States for 2008), and an LCD display with the analog tachometer and digital speedometer.
With a seat height of 31.9 inches the Shiver will be most welcome to riders of the long-inseam persuasion. Unlike most other bikes, though, how quick it’s going to be and how much go-power it’s going to generate when you twist the throttle will depend upon which electronic mode you select for it. Until recent years, when the rider rotated the throttle twist-grip, this motion actuated cables that physically opened and closed the butterfly valve(s) in the carburetor(s). In recent years, that physical connection in both automobiles and motorcycles has been replaced by electronics that read throttle position and do the actual opening and closing instead, based upon a number of parameters. And that’s not a bad thing. With the old cable-actuated carburetors there were always rideability problems when the engine was cold, so the rider had to manipulate a choke or fast idle control. And whenever the rider pinned the throttle, it could dump so much raw gas into the system as to cause stuttering and hesitation-not to mention wasting gas, increasing emissions and being hard on parts. Advances such as electronic fuel injection have largely eliminated those rideability problems.
Hit the starter button and the Shiver immediately settles into the sharp rap of a staccato V-twin idle, and this is where things get interesting. The Shiver’s “ride-by-wire” throttle control technology incorporates three modes: Sport, Touring and Rain. With the engine running and throttle closed, the rider can access these modes in turn on the fly by (get this) pressing the starter button quickly twice in succession. At this point the system toggles through the selections and the appropriate letter S, T or R will appear in the LCD instrument display. Any of the three modes can be accessed while you’re riding down the road.
Aprilia describes this as an electronic accelerator management system. To do its work it feeds such variables as engine rpm, gear selection, speed of throttle movement, engine operating temperature and even atmospheric pressure through a set of wires to the ECU. In an instant it reads various electronic “maps,” calculates what it believes to be the optimal throttle opening by balancing rideability and performance factors, then selects one and sends a signal to the injectors to squirt in the proper amount of fuel. According to Aprilia, the power and torque curves are the same in the Sport and Touring modes, and only the throttle response, the “feel,” is changed.
I set the Shiver in Sport mode, let out the clutch carefully (the friction zone is very narrow) and the bike leaped ahead, the exhaust note seemingly sharper than in the other modes; the rider can feel the power right off the bottom end. Shifting is light with just a slightly longer throw than expected, clutch pull is moderate and both levers are adjustable. Take the Shiver up through the gears and there’s torque everywhere, a good hit throughout the rev range and the bike feels like a sporty 750 with a bit of weight-induced lethargy. Calibration is overly sensitive in the Sport mode, however, as dialing in what seemed like a minor amount of throttle results in a greater amount of fuel than expected. Even the slight movement generated by traversing a series of bumps can cause intermittent lurching, making it difficult to modulate the throttle precisely. We also detected minor surging in the Sport mode. Unless we were really attacking the turns, we learned to just flip the Shiver into Touring mode (where we spent the vast majority of our riding time) which minimized this problem. Here, the Aprilia’s exhaust note sounds a little flatter, the engine winds up a bit more slowly and that hard hit in acceleration is diminished, but still thoroughly enjoyable.
With a short wheelbase of 56.7 inches, and rake/trail figures of 25.7 degrees/4.3 inches the Shiver is obviously going to be a quick handler. Not only is the engine extremely smooth (a 90-degree V-twin offers perfect primary balance), but torque is abundant all the way through its rev range, to its 10,000-rpm redline.
The most dramatic of the three settings is Rain, as once selected it feels as if the bottom (end) had dropped out of the Shiver’s power production. This mode is designed to prevent unwanted wheelspin during uncertain traction situations, and suddenly there’s much less torque than in other modes-you’ll need a bit more throttle to get away from a standing start. While our dyno runs showed peak horsepower as 75.8 at 9,200 rpm in Sport mode, Aprilia claims a peak of only 62 horses in Rain mode, and states that peak torque is likewise diminished by 5-12 lb-ft throughout the rev range.
We also found that, especially below 6,000 rpm, opening the throttle abruptly in fifth or sixth gear (as if you wanted to pass without downshifting) produced only lazy acceleration. Out here in Southern California we did not have an opportunity to ride the Shiver in the rain (oh, darn!), but our experience indicates that in Rain mode there’s not much chance of breaking traction under normal circumstances.
Aprilia fitted the Shiver with appropriate radial-mounted four-piston brake calipers on the front, hugging a pair of 320mm stainless floating rotors, the same used on the RSV and the Tuono. The rear single-piston caliper embraces a 245mm disc, braided steel lines are used all around, and braking action at both ends is solid, strong and predictable.
The Shiver’s bar and pegs induce the rider into a light crouch that, combined with a seat that really blends firmness with cushion, I was able to enjoy on a brisk 200-mile ride without needing to shift around for a more comfortable spot. And the windblast didn’t become near as tiring as it would have been on a bike that offered a more upright seating position.
Out in the twisties in the Sport mode the Shiver feels taut, the engine strong, its quick turning inhibited somewhat by its height and weight. Of course, by being tall there’s no problem with cornering clearance. Quick torque propels it out of turns, and those triple discs haul it back down with precision. With that wide bar and sculpted seat it’s easy for the rider to slip off, get a knee out and lever the bike through turns. The Shiver’s 43mm non-adjustable male-slider fork is perfectly adequate for the usual haring around, but its side-mounted shock absorber (it’s there to create more space for the mufflers) is less so. It offers spring preload and rebound damping adjusters only (which are easily accessible), but action is harsh over abrupt bumps, and we would have preferred less compression damping. Its Dunlop Sportmax Qualifier tires, a 120/70-ZR17 front and 180/55-ZR17 rear, grabbed tenaciously and offered good feedback.
Because of the plastic cover on its 4.2-gallon tank the Shiver will require a strap-on tankbag. It returned a respectable 46 mpg average in Rain mode, and 42.4 mpg overall. On our scales, the Shiver sent the numbers spinning to 486 pounds wet, which explained why the bike wasn’t quite as responsive as we’d expected. Though we haven’t tested any other 750 sportbikes recently, earlier this year we did test the somewhat smaller-displacement Ducati 695 Monster and Triumph 675 Street Triple, which weighed in at 419 and 420 pounds respectively.
Nits to pick? The sidestand is so long that it stands the bike relatively upright and could be problematic when parking in windy areas. Also, the stand’s tang is located so close in that it requires a major ankle bend to deploy. But overall we’re not complaining. The SL 750 Shiver packs a lot of performance and value for its $8,999 price tag, and is darn fun to ride! It’s a sportbike upon which one can also comfortably travel, and that’s saying a lot.
Ride-by-wire technology like that in the Shiver can smooth off the rough edges and make power delivery more controllable and economical. We could do without that throttle sensitivity and surging, of course, but even so, the Shiver is a ball to ride!
2008 Aprilia SL 750 Shiver Twin Spec Chart
Base Price: $8,999
Warranty: 2 yrs., unltd. miles
Type: Liquid-cooled, transverse 90-degree V-twin
Bore x Stroke: 92.0 x 56.4mm
Compression Ratio: 11.0:1
Valve Train: DOHC, 4 valves per cyl.
Valve Adj. Interval: 12,500 miles
Fuel Delivery: Electronic fuel injection, 52mm throttle bodies x 2
Lubrication System: Wet sump, 3.4-qt. cap.
Transmission: 6-speed, hydraulically actuated wet clutch
Final Drive: O-ring chain
Ignition: Digital electronic
Charging Output: 450 watts max.
Battery: 12V 10AH
Frame: Modular steel trellis w/ aluminum side plates
Wheelbase: 56.7 in.
Rake/Trail: 25.7 degrees/4.3 in.
Seat Height: 31.9 in.
Suspension, Front: 43mm male-slider fork, no adj., 4.7-in. travel
Rear: Single link-type shock, adj. for spring preload & rebound damping w/ 5.2-in. travel
Brakes, Front: Dual floating discs w/ opposed 4-piston radial-mounted calipers
Rear: Single disc w/ 1-piston caliper
Wheels, Front: Cast, 3.50 x 17 in.
Rear: Cast, 6.00 x 17 in.
Tires, Front: 120/70-ZR17
Wet Weight: 486 lbs.
Load Capacity: 395 lbs.
GVWR: 881 lbs.
Fuel Capacity: 4.2 gals.
MPG: 91 octane min. (low/avg/high) 40.1/42.4/46.0
Estimated Range: 178 miles
Indicated rpm at 60 mph: 4,300