With the RXV 4.5 – 5.5, Aprilia proves that development never stops as the world of racing is a continuous inspiration for road legal motorcycles such as the two reviewed today. Featuring an even lighter chassis than the previous generation model, an upgraded V-Twin motor and new design, the RXVs are some of the most highly acclaimed off-road motorcycles of this year.
Already a revolutionary engine for this class, the 77-degree V-twin gets even better as Aprilia developed a new fuel system featuring stepper motor throttle body control and new ECU. This change not only reduces weight and implicit makes the RXV more competitive, but also ensures fatigue-free starts during cold mornings. The other addition having much to do with engine performance is the new lateral exhaust system, which is the closest thing you get to a racing one. USA models feature twin under seat exhaust outlets.
Having improved the engine (making it better performing and lightening it), the chassis was to suffer the same treatment. The lighter rear frame now offers a lower seating position (5 mm lower, to be precise), perfect for the average-sized rider. Because ergonomics were modified for comfort, the bike also got a new seat.
Also at the rear end, the new swingarm makes no exception as it brings cast body and hydroformed members on the scene. Apart from reducing weight, this makes the new swingarm more flexible, keeping that rear wheel more on the ground rather than in the air and that can only mean better lap times.
Together with the lighter and more compact rear brake caliper, the overall weight reduction is of 2 kg.
Aprilia first introduced the RXV 4.5 in 2006 as a revolutionary bike that brought the V-Twin performance engine where only single-cylinder engines had previously managed to prove competitive.
Highly refined and an interesting alternative, the RXV was an immediate success on the global Enduro market, and it was soon followed by the 5.5 model a year later. This last completed the lineup and brought even more popularity to the Italian maker and its ingenious V-Twin engines powering the off-road bikes.
Later on, Aprilia improved the RXV engine and chassis and the overall weight was also reduced. Check out the previous RXV generation here .
More than decent single-cylinder powered alternatives to the RXV models are the KTM 450 EXC and 530 EXC. The KTM engine is a 449.3 cc (510.4 cc) single-cylinder four-stroke SOHC fed through a Keihin FCR MX 39 carburetor. It does indeed miss a cylinder compared to the Aprilia, but, like on a veritable off-road machine, the KTM engine is being exploited best in co-op with the six-speed wide-ratio gearbox. We can’t say the same thing about Aprilia which features a five-speed gearbox, something that unveils its race-oriented character.
KTM’s fierce competitor, and implicit Aprilia’s, is Husqvarna. Its Enduro range is practically defined by the TE 450 and TE 510 motorcycles which, like the KTMs, are powered by 449 cc and 501 cc single-cylinder four-stroke motors. Same case with Husky: it brings an extra gear in order to remain competitive in relation to the Aprilia.
In order for the RXV to look as good and inviting as it sounds, Aprilia gave it a nice, race-inspired look while keeping an eye opened for details. The typical Italian style is defining, starting with engine, frame and ending with the headlight and plastics.
The V-Twin is small and compact, very easy to be mistaken with a single-cylinder, as the innovative design of the frame masks big part of the engine. Underneath the powerplant, a protective plate gives a clue about this bike’s off-road capabilities as well as the redesigned swingarm.
Fairly big and imposing, the RXV rides on a pair of 21-inch front, respectively 18-rear wheels featuring matte black paint on them.
In what concerns the finishing touches, they are top notch. The RXV is packed with angular lines among which in the front end, designers managed to include the nicely styled headlight. Highly positioned, the front fender further enhances the aggressive attitude of this off-roader.
Ingeniously built, the fixed air ducts allow the fuel tank to tilt up for easy access to the air filter box. On the sides, panels featuring the maker and model name uncover the mystery behind it. The two-tone colored seat integrates perfectly in the harmoniously built Italian bike that the Aprilia RXV is.
Color combination for 2010 is Red, Black and White.
"Its fuel injected, liquid-cooled, titanium valved 449cc v-twin is stout, its 45mm upside-down fork and rear hydraulic monoshock offer loads of travel, and the whole package weighs in at only 262 pounds, dry." – motorcycles.about
"The power band on the small 450cc V-twin puzzles me a bit still. It is still very much racing and there is a big dip in the curve before all hell comes loose. But with the Akropovic single muffler the throttle response is massively improved." – raptorsandrockets
"The RXV 4.5 is light and flickable! For off-road, the flat seat, combined with the very narrow tank-seat junction means that there’s not a lot of mid-section for the rider to grip with the legs. This puts more strain on the upper body to maintain the correct riding position.” – ultimatemotorcycling
"The twin-cylinder of the Aprilia SXV 5.5 offers unprecedented rider-friendliness. The abundant mid-range torque has a lot to do with it. I was pleasantly surprised to see how easy it is to keep pace with a superbike on ultra-twisty roads (at legal speeds, of course). When the road gets bumpy and corners become sandy, the SXV is unbeatable due to its feather weight and unparalleled handling." – moto123
An MSRP of $8,599 for the RXV 4.5 and one of $9,299 for the bigger versions is sure to leave future owners wondering if wouldn’t it be better to buy the cheaper model and start googling for aftermarket pipes and so on, in order to achieve the same engine performance as on the significantly more expensive 5.5 model.
The Aprilia RXV 4.5 – 5.5 is a true demonstration of power off the road as there are being made continuous improvements to this bike so that it remains an incontestable leader of its class. Also, due to its style and ingenious construction methods applied, the RXV is also a good way of being introduced to Italian machines, which are now conquering every single bike category.
Engine and Transmission
- Total displacement: 449 cc (549 cc).
- Type: 77° V twin four-stroke. Liquid cooled. Single overhead cam with rocker operated exhaust valves, chain timing drive. 4 valve heads with titanium valves.
- Fuel: Lead-free petrol.
- Bore x stroke: 76 x 49.5 mm (80 x 55 mm).
- Compression ratio: 12.5:1 (12:1).
- Fuel system: Integrated electronic engine management system controlling ignition and fuel injection, with two power mappings.
- Throttle body: 38 mm (40 mm).
- Ignition: Electronic.
- Starting: Electric starting.
- Alternator: 340 W.
- Lubrication: Dry sump with external oil tank. Separate gearbox lubrication.
- Gearbox: 5 speed.
- Enduro gear ratios:
- 1st 12/31
- 2nd 13/25
- 3rd 15/23
- 4th 19/24
- 5th 21/22
- Clutch: Cable operated multi-plate wet clutch.
- Primary drive: Spur gears.
- Transmission ratio: 22/56.
- Final drive: Chain.
- Transmission ratio: 15/50 (Z14 sprocket supplied).
- Exhaust system: Euro 3 lateral exhaust.
- Conforms to FIM regulations for 2010.
Chassis and Dimensions
- Frame: Chrome-molybdenum steel perimeter frame with aluminum alloy vertical members. Steering head (rake) angle 27°. Lightweight rear frame.
- Front suspension: Ø 45 mm upside down fork with two adjustments.
- Rear suspension: Aluminum swingarm with cast body and hydroformed members. Hydraulic monoshock with compression and rebound adjustment.
- Brakes Front: Ø 270 mm floating disc in stainless steel with aluminum flange. Nissin floating caliper. Rear: Ø 240 mm stainless steel disc with floating caliper.
- Wheels: Black anodized aluminum alloy.
- Front: 1.60 x 21”
- Rear: 2.15 x 18”
- Tires: Front: Metzeler 90/90 x 21”
- Rear: Metzeler 140/80 x 18”
- Overall length: 2,222 mm
- Overall width: 800 mm
- Ground clearance: 396 mm
- Seat height: 941 mm
- Wheelbase: 1,495 mm
- Fuel tank: Capacity 12 liters