2008 Aprilia SXV 5.5 Review - Motorcycle.com

But there are very few production supermoto machines available from the OEMs. Plus, the vibrations of those single-cylinder models can turn a freeway stint into an exercise in endurance.

Enter the V-Twin Aprilia SXV models, available in 450cc and 550cc versions and now street-legal in all 50 states. Naturally, we opted for the bigger, more powerful SXV 5.5, which induced huge, s*!t-eating grins from the very first mile.

'...it feels odd to be pointing such a machine into the mean streets - the presence of a license plate and turn signals are the only obvious nods to being street-legal...'

Anyone who has experience with dirtbikes will find the SXV’s cockpit familiar. A rider is greeted by a tall, narrow saddle, a tapered-aluminum handlebar and an ultra-thin midsection. Combined, it feels odd to be pointing such a machine into the mean streets - the presence of a license plate and turn signals are the only obvious nods to being street-legal.

The first hint of a nasty attitude is experienced at start-up. Instead of the idle being controlled electronically, the SXV offers a choke/enrichener lever - quite an anachronism in this fuel-injected age. With it engaged, engine revs soared to a lofty 5,200 rpm on the tach of our test unit (although Aprilia says it should be closer to 3,500 with the latest ECU mapping). Once warmed, it still has a high 2,300 rpm idle. The SXV is barely housetrained compared to a typical Honahakazuki.

The tiny V-Twin engine breathes through four titanium valves per cylinder that are fed by a pair of 40mm throttle bodies. Power rises in a linear yet entertaining fashion until 9,000 rpm when it flattens out around the 60 hp mark but keeps pulling until its 11,500 rpm rev limit, as recorded on Mickey Cohen Motorsports' dyno. The dry-sump motor was good for nearly 62 hp and 35 ft-lbs of torque at their peaks. It exhibits a very light flywheel effect, revving up extremely snappy.

Zesty engine response and short gearing results in first-gear wheelies with just a whiff of throttle. There’s only about 300 lbs to tow around, thanks to expensive weight-reduction components such as magnesium engine cases and titanium valve cover fasteners. Short-throw gearshifts happen quickly, as a rider can be in fourth gear just seconds after launching. Gearing inside the five-speed tranny (a sixth would be nice) is so short that second-gear starts are easily accomplished and generally preferable. Clutch pull is one-finger light.

I'd suggest fitting different sprockets to produce a taller final-drive ratio. This would make the lower gears more usable on the street, plus it would calm down the bike’s demeanor at highway speeds. The chassis feels comfortable at 80 mph, but the vibration through the handlebar at 7,700 rpm is excessive and tiring. Not that the bike’s narrow seat will allow long stints, anyway. Aprilia says its 77-degree V-Twin vibrates less than any Single, but it has no balance shaft and isn’t smooth at high revs. BTW, the bike’s numeric tach is impossible to read while riding and slow to respond. A tiny LCD bar graph across the top of the gauges also serves as a tach, but it’s too small to be readily seen.

'set the Aprilia’s nose toward a sinuous canyon road, and there’s no bike in the world that can give you the visceral thrill of the SXV.'

These quirks, however, don’t detract much from the SXV’s incredible grin-inducing qualities - let the more practical riders buy a V-Strom. The Priller is different, distinct, and as pragmatic as Paris Hilton.

Set the Aprilia’s nose toward a sinuous canyon road, and there’s no bike in the world that can give you the visceral thrill of the SXV. It’s alive with sensations. It leans into corners as quick as you dare, and it steers with not much more effort than a heavy mountain bike. The diminutive but potent engine feels directly connected with the rear wheel. It’s a sweet motor with tons of grunt - wheelies happen everywhere. This bike makes a familiar road seem fresh and exciting, accompanied by a tuneful song from its bitchin’ underseat exhaust.

The SXV’s chassis has been proven at the world level of supermoto racing. It’s a steel trellis skeleton press-fitted into forged-aluminum sideplates, using the engine as a stressed member. A beefy 48mm Marzocchi fork is three-way adjustable, while the Sachs shock also includes a separate high-speed compression damping circuit. Aprilia altered the SXV’s suspension for the 2008 model year, with a new rising-rate shock linkage for the variable-section aluminum swingarm and tighter damping specifications. The fork also received damping increases for better control.

The long-travel suspension nicely absorbs bumps, but a shorter suspension would be appreciated, both to reduce its tall 36.1-inch seat height and to mitigate the considerable amount of front-end dive when tapping into the brawny power offered by the radial-mount monoblock caliper and 320mm wave-style front disc. A lightweight single-piston caliper at the rear bites on a 240mm rear disc.

At a tank-empty weight of just under 300 lbs, the SXV 5.5 provides an enviable power-to-weight ratio, with each peak pony (61.8 hp at the rear wheel) pulling less than 5 lbs. For comparison, a Ducati Hypermotard has about 78 hp but weighs 420 lbs with its tank empty, resulting in a 5.4 pound-per-hp ratio. A broad spread of torque ensures immediate response. New for the 2008 model year is a two-stage engine mapping program.

When the SXV and enduro sibling RXV were originally introduced, there was some concern over the durability of the engine for extended high-rpm street use, perhaps the reason why the bikes weren’t initially street legal in the U.S. But Aprilia’s Brand Manager, Rick Panettieri, told Motorcycle.com that the engines have received many tweaks since they were first available. “There have been many changes over the past few years since the bikes were introduced in Europe, including improved suspension settings and improved starters and pistons,” said the Aprilia/Guzzi rep. before adding, “All these changes allowed us to extend the maintenance intervals and warranty periods (six months). The engine has proven to be very durable when it is properly maintained, even in supermoto and road-race conditions.”

As an overall package, the SXV is a bit short on polish. It’s Italian in the old, quirky Italian way. Its sidestand looks cool but is wildly overbuilt, and its self-retracting spring is a hassle. Also, a 3.2-gallon gas tank and a voracious hunger for fuel (about 30-or-so mpg) results in a limited range.

Combine the above with its tall seat and its considerable $9,499 MSRP (the 450cc version is $700 cheaper), the SXV 5.5 represents a minimum of practicality, so this isn’t the bike for the pocket-protector set.

But if you’re a former or present dirtbike rider with a dominant yee-haa! gene, you can’t find a more exciting street-legal two-wheeler at any price.

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