Looking at a World Superbike Championship race, where liter class sportsbikes battle for a podium position, and your evening's entertainment will never been the same. Aprilia's RXV 4.5 has the potential to do the same to dirt bikes. It's the first 450cc V-twin for an enduro type of bike. It's lighter and smaller than many singles cylinder enduro bikes, and by any standard, it's fast.
The Aprilia RXV 4.5 makes a big first impression with its indulgent design. It's all sharp lines and flamboyant angles, if you're looking for a mental toy though, style matters.
Fuel injection, a clever ECU, and a reliable electric start remove one of the worst agonies of enduro riding, thrashing away at a hot engine's kickstart after the battery has rolled on its back. If you put an enduro rider in the desert they'll walk in a big circle thanks to having one over-developed, kick-start leg. No kidding.The Aprilia RXV 4.5's performance is as impressive as its practicality. The throttle pick-up is brilliant from closed with no hint of snatch, and you get instant drive. Low rev pull isn't its strength, though you won't go short before the steaming midrange arrives. Pin it at this point and it takes off like a rocket. Peak power is more useful and less dramatic than you'd expect. It doesn't explode into a short spike of violent thrust, as Aprilia created a long, flat climax that gives you lots of over-rev and easy access to the majority of power. And with 55 horses to pull you out of the dirt, about 6 horses more then the previous single cylinder horsepower king the Honda CRF450X.
There's a major flip-side to the engine character though. Drive comes in so hard and fast that even the first two millimeters of throttle cable will wrench your arms and break traction. It's tiring to ride and difficult to make the power count. It would take a real expert to show the Aprilia RXV as the thumper muncher that it can be. It is clear to me, that as Honda CRF450 rider, I need to learn to control the power.
The chassis aims as high as the engine. It's agile, with no noticeable inertia penalty from the V-twin's crank, and it remained stable even when tapped out in fifth at 125km/h on a rural gravel road. The brakes are strong, and more importantly offer loads of feel over constantly changing surfaces.