Aprilia RXV550

WHAT IS IT?
A version of the firm's much-talked-about V-twin dirt bike series.

WHAT'S IT LIKE?
Innovative and damned fast, with a few wrinkles still to be ironed out.

THE BIKE
The first Aprilia RXV550 to hit the market in 2006 was an animal. It was scary. It had a light switch for a throttle and more ponies than the Ponderosa. On a test day, while doing 140kph on a flat dirt road, I listened to the rear wheel screaming for traction and wondered how you'd ever get the thing up a hill - and how I was going to pull up at the next corner. I wasn't keen to get back on it any time soon, and yet here I am, all suited up and ready to roll on the 2007 model of the wicked Italian.

BELLEZZA (Beauty)
What I see before me is still the best looking dirt bike ever crafted. Italians know style and when the quest for the balance between form and function is serious chased, they often come through with the goods - they invented the Yo-Yo for heaven's sake! And of course the Ducati, MV Augusta, and Cagiva, not to mention that Aprilia's own stunning gifts to the road bike world are all, 'messo in modo bello' (beautifully crafted).

It's hard to know were to start when describing the RXV. It's predominantly black and red colour scheme is striking, as is the Lions head on the radiator shrouds and the super aggressive front and rear guards. Then there's the frame - or lack there of. The forward part of the frame is non-existent and the job is instead done by making the engine a structural part of the bike. It looks great, but there's nothing to stop the engine from taking a direct hit from a log or ledge, so a bashplate is a necessity. It's packing a fairly healthy 396mm of ground clearance however, which compares well to the current king of the big-bores, the KTM 530 EXC-R, which has 380mm.

The twin pipes slink their way up under the seat and peer out from under the rear guard. Heat can be felt as it builds up under the seat but it's not unbearable, and anyway, we reckon those pipes look so sweet you can take some heat for the pleasure.

The speedo is a very compact and sturdy looking LCD unit that tells you everything you'll need to know, with a scroll button cleverly mounted on the left-hand switch block. The keyed ignition means you can stop for a pie and not be so worried that a scumbag will pinch your bike.

To access the paper air-filter you have to get under the tank and it's a fiddly job that doesn't suit a dirt bike all too well. Overall, access to the engine isn't easy given that the twin cylinder donk takes up every available millimetre of space. It looks like something you'd see on a road bike but doesn't lend well to on-the-trail, middle-of-nowhere maintenance. The seat comes off easily enough through a single Dzus fastener, while undoing a hex bolt near the steering head allows the fuel tank to hinge upwards to reveal the airbox - underneath which is the engine - but not much room to do anything with it.

None of the RXV's beauty is diminished - and even a few of its shortcomings are forgotten however - when the engine fires to life. It revs in short, sharp explosions of power, testosterone and deep guttural joy. If Harley owners are still under the impression that their bikes sound fantastic, they best not saddle up next to the RXV at a set of lights because it'll destroy all their dreams and rattle their tassels to the core. Stop me if I'm gushing, but I went through half a tank of fuel just revving the bike in-between gear changes.

So, after a look at some construction details, you'd have to say the RXV is a little more form than function at this stage. Let's get it on the dirty gear and let the ponies run.

FLAT AND KNACKERED
Staring the RXV was a problem. The battery was dead and didn't build any charge even after several hours riding. It was a push start for the whole day, and I don't need to tell you how much that sucks in 34 degree heat and on flat ground with a 119 kilogram plus (claimed dry weight) machine. Neither the 450 nor 550 have a kickstarter, and fuel injected V-Twins take some voltage to get fired-up. Function was loosing to form again.

RAZZO ITALIANO (Italian Rocket)
Power your way through gears for the first time and you very quickly find that this bike's like nothing else on the market. If the RXV's problems are sorted, Aprilia has something very special on their hands with this engine. The power is still monstrous but the delivery has been cooled. It's much more controllable over the '06 model, thanks to a new oval design in place of the original round kit, and the way it feels when you open the throttle is near a religious experience.

The engine is smooth and the bike shows no vibration as you wind your way up the track, where the queue to change up a gear is given when the rear wheel is spinning faster than the earth's rotation can match. With all that power to play with, it's surprising how easy it is to keep it in check and pick your way through tight stuff. And believe us, it's obscenely fun. Sure, it'll catch you out every now and again, and it's not unusual to find yourself completely sideways with no notice, but it never seemed difficult to bring back in line, even when seemingly we were past the point of no return.

Up front, the fork does a great job over most everything, but the very quick steering can have the RXV pushing through turns, deflecting off sharp ledges, and off camber corners are a bit nerve racking. A bike this strong can afford to have slower steering because you can steer with the back wheel. The rear end has the dubious job of keeping as much of the bike's power to the ground as possible and still soak up the hits. It does kick at times under braking, but a little tuning would probably help there. The breaks are, thankfully, excellent. They're strong, predictable and well balanced on any surface.  

Although we had to push start it every time we stopped, the Mad Monkey test crew were still upbeat about the RXV until the unlikeliest problem arose. After 47 kilometres, the fuel light came on, and since the bike is fuel injected, there is no reserve. This is no good. A big bike should take you a long way. Hell, even a little bike should take you more than 50 kilometres. So, after pushing it all day in the heat and then - halfway through our usual ride distance - the bike starts running out of fuel! We got the shits and called it a day. We were out of fuel at 50 kilometres and wow, what an amazing 50 kilometres - but a twin cylinder enduro bike of this size needs more than a 7.8 litre tank.

ALMOST THERE
All that power produces wheelspin that robs the bike of juice and destroys rear tyres in a flash. Is it worth it? Kinda.

The bike is in its second year of production. If Aprilia engineers are on the ball and the fuel, battery and front-end issues can be sorted, I'll put my hand up for one in my garage. It's simply the most exciting bike we've ever ridden - the most amazing big bore engine on the planet - and there are some other clever ideas at work here. Give it some time and hopefully it will come of age, but right now the ledger is more on the form than function side, and although the RXV is a blast to ride, I don't think I'd want to live with it…yet.

WHAT THE BOYS SAID:

MARK HARGRAVE - Expert