Aprilia’s voyage into the off-road market is finally bearing fruit for the Italian company. The rumors have circulated long enough and it was almost a relief to finally set the story straight with our own MotoUSA test.
Every so often there comes a bike that has the potential to help revolutionize motorcycling. Bikes that were developed out of forward thinking, innovation and creative design. It’s the nature of motorcycle enthusiasts to find a way to do something different or better, which is the cornerstone of evolution in our sport.
Off-road motorcycles have seen huge advancements over the past five decades: Yamaha’s affordable and reliable DT1; the first monoshock on the 1975 YZ250; water-cooled engines; Honda’s aluminum-framed CR250 in ’97; and the now-rampant 4-stroke revolution of 1998 and beyond. Not every new idea blossoms into an industry-changing standard, (remember Cannondale?) but that’s precisely what Aprilia is shooting for with its 2007 off-road lineup.
Aprilia decided to reveal its RXV enduro and SXV supermoto bikes to the American press at an East Coast intro. My voyage led me from our Oregon HQ to a New Jersey airport, Pennsylvanian hotel and finally a New York race track. Though I knew little about the bikes, I knew even less about our destination in BFE, known locally as Cuddebackville, NY. As it turns out, the Oakland Valley Race Park nestled along the outskirts of a dense, lush forest offers a very fun supermoto course. Supermoto/ex-motocross hero, Doug Henry actually conducts his SM tutoring at the facility, and those nearby woods gave us a rooted, twisty stomping ground for an enduro test.
Oakland Valley Race Park in Cuddebackville, NY was our host for both supermoto and enduro testing. Those densly-wooded forests surrounding the paved track gave us a typical East Coast trail; tight, twisty and full of roots.
By the time I arrived at the hotel I had been in airports and shuttle transports for over 12 hours with only a package of crackers to survive on. But, as tired and hungry as I was, the thought of feasting my eyes on Aprilia’s beasts was more appetizing than our eventual plate of turf-and-tail. Unfortunately, Aprilia personnel wouldn’t show their cards until the following day as we took to the track and trail bright and early. We were treated to a plethora of bikes to ride in the form of stock and race-kitted enduros and supermoto machines. Riders of either racing discipline can choose between the 4.5 and 5.5 models which, as you might have guessed, are 450cc and 550cc, respectively.
Having already assaulted the European and World racing circuits, winning the 2004 supermoto world championship in the S2 class, Aprilia is trying their damndest to breach the U.S. market.
There’s going to be a new name on the lips of enduro racers in America. Europe has already seen the capabilities of Aprilia’s RXV series, and the Italians want to ensure that U.S. racers do also.
Leading up to the intro, everyone has been talking about the V-Twin, fuel-injected engine, which was high on my interest list, but the feature that really stokes my fire like gasoline is the frame, bodywork and styling. The RXV looks like no other bike. If you thought KTMs were angular, take a look at the Aprilia off-roaders.
Given the Ducati-esque rear fender, wave brake rotors and under-tail exhaust, the RXV drips with European styling. In a lot of ways the Aprilia is like a bulimic Italian supermodel. With a pointy beak, the high cheekbones of the fuel tank, protruding ribs of the trellis frame and long-legged ground clearance, the Aprilia creates lines from tip to tail that’ll have men gawking, slack-jawed at every turn. Some people think these sharp-featured supermodels are too thin, but all arguments about social norms aside, the fact is that these creatures are a symbol of beauty. The new Aprilias are exotic and sexy.
Once the motor comes to life, the similarities stop. Those coked-out waifs can hardly manage to remain standing for a full day of photo shoots, but the RXV barks to life and lets you know instantly that it isn’t some malnourished machine. Toe the five-speed transmission into gear and the bike proceeds to kick the living crap out of everything in its path.
Small, compact and very powerful, Aprilia’s V-2 motor has an enormous amount of potential in off-road applications.
That V-2 motor I was talking about has a pair of stubby, 76 x 49.5mm bore/stroke cylinders (80 x 55mm on the 550) which rest at a 77-degree angle. The result, says Aprilia, is a maximization of performance with minimal vibration. Claimed horsepower sits at an lofty 60 hp (measured at the crankshaft of the stock 4.5), while the 5.5 churns out 70, the same numbers as the SXV models.
Of course, we didn’t have a dyno on hand to verify, but those are some impressive numbers. Even with a 10-12% reduction by the time the power reaches the rear wheel, we’re still talking about 50 horses, which is way above anything we saw from our 2006 450 Enduro Shootout contenders (the gnarliest of which, the WR-F, made 43 peak ponies). It even tops the moto-specific Honda CRF450R that produced a maximum of just over 50 hp at the rear wheel. We’ll have to wait for further testing to get the real numbers, but the bikes definitely make a ton of power. Obviously the 550 is stronger, but from the seat of my pants, I’d judge the 450 to have more nuts than the ’06 enduros we tested.
The Italian company has developed race kits for each bike of the enduro and supermoto categories. The RXV race package includes a specifically tuned titanium exhaust which produces a claimed 2.4 additional horsepower on the 450. The kit also removes the throttle body restriction, has a lighter, all-plastic headlight/front number plate, removes the computer and comes with a special electronic ignition key. All told, the race kit allegedly makes the bike 10 pounds lighter.
The first thing I noted about the stock 450 was how hard the motor exploded, only a split second off idle. Next up was the race-kitted 450 which was even burlier, and then the 550 reversed the last three years of healing in my torn rotator cuff. Electronic fuel injection feeds the 450 through 38mm throttle bodies while the big-bore model utilizes 40mm feeders. The dual throttle bodies fit between the cylinders, keeping the entire package compact and aiding in a low center of gravity. To give you an idea of how compact the motor is, Aprilia was able to fit the airbox on top of the throttle bodies and under the fuel tank.
Twist the throttle and the dual 38mm throttle bodies of the EFI get things moving in a hurry. The 550 is incredibly powerful but wasn’t as effective as the 4.5 in the tight woods. It’ll bring out the horsepower freak in you, though.
A single overhead cam operates four titanium valves. Dry-sump lubrication handles claimed engine speeds of up to 13,000 rpm on the 450, but if you do experience a melt-down, the cylinders’ replaceable wet sleeves will give riders extended rebuild potential. Pressure inside the cylinder comes in the form of a 12.5:1 compression ratio in the 450 and 12:1 in the 550.
Gaining access to the engine couldn’t be easier. The seat comes off with the twist of a single Dzus fastener. Next, remove a single hex-head bolt near the steering head and the 2.1 gallon fuel tank hinges upwards like the hood of a car, held conveniently out of the way with a cable stashed next to the battery, also under the seat.
Search all you like for a kick lever, but starting either model is only possible by using the electric starter. The unit worked fine on all of the bikes tested and there weren’t any dead batteries throughout the day. That doesn’t mean that it won’t happen though, and I’m a bit leery of any bike that doesn’t have the kickstart option. At least with the supermoto version you probably won’t be stuck 50 miles from your truck.
Californians will be happy to know that both bikes are Green Sticker-legal, so you won’t have to pull any funny registration business with your Arizona neighbors. However, Aprilia did miss the mark with street-legal standards. We’ve been told the dirt-oriented motor doesn’t have the durability to meet the requirements for U.S. streetbike use, even though the bike does meet current exhaust emissions standards. Also, the blinkers and lights are not DOT approved.
So, the technical and design aspects looks great on paper and even better in the real world, but what matters most is how it all comes together on the trail. First off, the motor is awesome. Tons of power and hair-trigger throttle response make this a mean machine. However, it can be a bit too mean, especially on the 550.
Its bottom end has plenty of power, but there was a slight flat spot immediately off idle on all of the RXVs. We’re talking about super-low rpm here, hardly detectable. After that, the fireworks really start with super-abrupt delivery that reminds me of a 450cc motocrosser. It has a smooth powerband if you’re rolling on the throttle, but on-and-off jockeying through tight terrain makes the bike seem harsh because the response is so fast and there’s so much of it. By the end of the day I was dying to get a stiffer set of suspension and take this bike to Washougal. Aprilia did say that an MX version was in the works and slated to appear sometime in the middle of next year.
Because the enduro course was so tight, I was confined to using only three of the five gears. Wringing it out in first and second shows great over-rev from the V-2, reaching all the way to 11,500 rpm on the 450 and 11K rpm with the 550. It was high and it was impressive. Not only does the bike have a high rpm limit, but it gets to it very quickly. The motor spins up and makes power a lot harder and faster than some other 450 enduros. I pegged this as a lightweight flywheel issue which was also noticeable in the bike’s penchant for stalling. Aprilia’s supported this with its claim that the flywheel is “far lighter than any single cylinder machine.” When that motocross version does come out, the quick-revving characteristics will be great, but a heaver flywheel effect would be preferred for enduro purposes.
Even though it’s a V-Twin, the Aprilia powerplant still has the same features of today’s modern single-cylinder 4-stroke: tractable power, amazing torque, high-rev capabilities and plenty of ponies.
Rowing through those first few gears was easy with the cabled clutch keeping my left hand in constant communication with the motor. With so much power, I found that first gear almost wasn’t necessary, even in the tightest areas. Riding a gear high and fingering the clutch lever was just fine with the motor and helped ease the big power surge, especially on the 550. Truth be told, I had no need for something that big on a course like the one we were provided. Aprilia apparently realized the limiting factors and didn’t bother to bring a 550 with a race kit, thankfully I say. The stock bike alone needs some wide-open spaces if you want to reach its limits.
The more power I got from the bikes with the race kits and bigger motor, the faster I started to hit obstacles. I was using the same gear selection and throttle, but things were happening at a much faster pace, illuminating characteristics such as braking and weight. The tank-empty 450 weighs a claimed 271 pounds, though it feels as light, if not lighter than, the 450 enduros we tested earlier. Aprilia has done a magnificent job of hiding the weight which is said to be identical for the 550. However, when riding the bikes back-to-back, the 550 feels heavier.
Dodging tight trees and moving side to side is very easy because of the nimble feel and well-placed controls. Whipping the bike through a 180 on the trail was easier than any of the 2006 enduros we tested, despite having a seat height said to be more than 39 inches. I didn’t have nearly the trouble reaching terra-firma as I should have at that height.
Front to back the bike feels neutral and well balanced, but the rear end feels light when applying the brakes – even when using just the rear 240mm wave rotor and floating single-piston Nissin caliper. It takes careful modulation to ease the back binders, as the lightness under braking makes the rear pedal more of an on/off switch. Up front the wave rotor is 30mm larger and it gets the squeeze from a dual-piston caliper. That brake works excellent.
We were happy to find that both brakes work exceptionally well, especially the front unit. With more and more manufacturers going to wave-style rotors, Aprilia stayed ahead of the curve by bolting on a set of Braking’s bumpy binders.
With so much power, the RXV lightens the front end while accelerating hard. The bike definitely transfers weight rearward and induces wheelies, despite the Aprilia tech’s assertion the suspension had the proper amount of sag for my weight. This caused me some problems in the handling department. Another concern I had with the shock is that the reservoir is placed less than an inch away from the portion of exhaust where the two headers converge into one large rectangular section. Without a heat shield, my first thought was that shock fade would be compounded as the raging heat waves boil off the exhaust. But, technicians assured me that nothing of the sort has taken place during any of Aprilia’s testing, and I never felt anything out of the ordinary on my ride. By ordinary I mean great. The rear end was awesome on every obstacle.
I found myself wishing that the 45mm Marzocchi fork could match the performance of the rear end, but instead it was jittery and vague. Moving hard down straights, any time the front wheel hit a rock, root or stick it transferred a lot of that impact to the rider and moved away from the obstacle rather than absorbing it. The deflection wasn’t severe, but it was enough to be unsettling and make you constantly think about it.
Likewise, I had a hard time getting the front tire to bite and settle into corners no matter how far forward I crammed by body. After discussing the issue with factory race team manager Stefano Passeri, by way of interpreter, he softened the compression three clicks and slowed the rebound five increments. The changes did improve minor deflections, but it was still nervous. The change didn’t give me the confidence I was hoping for in the corners either. It isn’t that the fork is bad, just in need of fine tuning. Unfortunately, I didn’t have enough time or speak enough Italian to get it all sorted out. The 16 pounds of pressure in the 90/90-21 Michelin Enduro Comp III front tire likely added some of the harshness, about 3-4 lbs more than I’d choose for similar terrain.
I thought it was a bit strange to have the shock reservoir so close to the muffler, but technicians have yet to find any performance flaws due to excessive heat.
Another area where our initial ride fell short due to the limiting course was in dissecting the perimeter chassis. The upper sections are a tubular steel trellis design that mate to pressed aluminum side plates. The result is a kick-ass visual affect and from what I could tell at our lower speeds, a very rigid structure. That V-2 engine acts as a stressed member of the frame, and all told the bike has 15.6 inches of ground clearance and a 59-inch wheelbase that is up to an inch longer than other enduros.
Attaching the 140/80-18 rear tread is a variable section aluminum swingarm that looks like it belongs on a CBR600RR. Boasted as the stiffest swingarm of any off-road motorcycle, I don’t doubt the claim. It looks bitchin’.
Ergonomically, riding the Aprilia is comfortable with a neutral spatial layout. The bars might be considered a bit laid back, but rotating them forward managed to get them close enough for my tastes.
One extra bonus of the angular styling is the ridge on the fuel tank and radiator shroud actually provide a ledge to hook your knee under. This is a big help in controlling the bike because you can exert pressure by wedging your leg between that ledge and the footpeg, and it allows the rider to rely less on squeezing with the inner thigh. Standing up, the natural position is more rearward where a rider’s knees contact a flat plastic surface rather than the tank ridge. This works pretty well, but the smooth polymer is devoid of any graphics and provides absolutely no friction. Another reason it’s hard to grip the bike with your legs while standing is that the lower aluminum portion of the chassis tapers inward, leaving only a small contact patch at the ankle.
Like with most bikes, there was an issue or two with the suspension that was a challenge to resolve. In this case it was a jittery Marzocchi fork that we managed to improve but not perfect.
Both the enduro and supermoto come with a multi-function computer. The digital readout offers plenty of features including a tach, speedo, turnsignal indicator, tripmeter, clock and warning lights, all of which are accessible through a scroll button mounted at the left grip. As great as that might sound in concept, it’s far less useful in practice. The speedometer can’t keep up with the bike’s acceleration and the rpm gauge is even worse. That useless fea