Bikes - Bike Tests

'07 Aprilia V-twins

Published: 18th January 2007

Author: Words by Gareth Edmunds Photos by Aprilia

Sleek Chic! With regular enduro test pilot Geoff Walker otherwise engaged we enlisted the help of Tommy Searle's wrench Giz Edmunds - Jonty's even more beautiful baby brother - to take a pair of '07 Aprilia V-twins for a spin.

The Aprilia RXV is a bike I've always loved the look of because of its sleek Italian styling and also because it's so different - in a world of single-cylinder thumpers the Aprilia twin four-popper is different with a capital D.

The designers haven't been shy in breaking the conventional bike building mould and producing a machine that looks like no other. But while thinking outside of the traditional bike-building box, the engineers responsible for the bike have also designed a machine that's designed to be as simple as it possibly can.

The bikes at the 2007 test were fitted with the race plastics kit which comes free with the bikes as part of the spares pack making what was already an eye-catching machine now even more stylish and a lot sportier - like a proper enduro machine, not a trail bike.

The bikes come fitted with high quality products as standard which shows they're designed for serious competition and not just to be mechanical eye candy. The machines are littered with quality parts - Marzocchi front forks, Nissin brakes matched with Braking disks, Domino throttle and clutch assemblies and Magura oversized bars.

With the bikes being both visually and mechanically appealing the idea of riding - and racing - a V-twin is very tempting and it'll be interesting to see how an Italian-built twin-cylinder enduro bike compares to other European and Japanese single-cylinder thumpers.

With the guidance of former world enduro champion and now Aprilia's WEC team manager, test and development rider Stefano Passeri, I arrived in a small village in the Italian hills where we were met by a team of technicians with the new '07 RXV range.

Firstly I decided to take the 450cc bike for a spin as the thought of getting straight onto a 550cc machine didn't appeal.

The electric starter fired the bike into life straight away. But then it stopped again. One of the technicians came over and told me to hold the throttle partially open. This worked as a choke, of sorts. The test bikes had different throttle housings to those fitted to the production bikes which will come with a small button on the housing which opens and locks the throttle to simulate what we were doing manually. This is then released when the throttle is opened further once the bike is warm.

The previous evening the head of development told us one of their main focuses for the new range was trying to reduce the hard-hitting characteristics of the '06 model. They had worked hard on improving the ease-of-use of the engine by concentrating on the bottom-end of the power range as this was too aggressive on the previous year's model.

As we rode up a slippery rock trail I could see straight away that they have achieved this. The power delivery was very smooth and useable and the engine kept on pulling and pulling but not in a brutal way. Obviously, if you really revved the engine it would hit harder and spin the rear wheel but this is only to be expected with any large four-stroke. The bike seemed to track really well when ridden smoothly on the rocky terrain.

As we rounded a corner at the top of a climb we saw a fast flowing, smooth trail. I was interested to see what the bike was like when it was opened up and it didn't take me long to see that this bike had very strong mid to top-end power. It wasn't arm-wrenching but very progressive and strong. The engine continued to pull and pull and didn't seem like it was ever going to die off.

Although the power was good the front end of the bike didn't feel as positive as I'd have liked. The bike did feel like the weight was very centralised and I found it hard to transfer that weight forward onto the front wheel to get the bike to grip but I think this was more due to the front wheel being fitted with an intermediate tyre rather than the mud tyre needed for the conditions we were riding in.

As I came to a slower twisty section in the middle of the fast trail I felt how good the Nissin brakes were. It's nice to find a European bike with strong brakes with a good feel - something I think has been lacking and over-looked by many other enduro bike makers. The Nissin calipers with the Braking wavy discs worked faultlessly all day.

Once we got to the end of the trail we dived down into a technical ravine which gave a good impression of how the bike would work in typical UK enduro terrain. The bike was easy to ride down the gully with the brakes giving confidence to push a little harder. The suspension felt good and seemed to now transfer the weight better as we were going downhill and it coped well in soaking up everything in its compression stroke as well as being equally as good on the rebound as it didn't seem to return too quickly and fire me off rocks. It seemed to follow the path I wanted to take everywhere.

I also found that the bike had very good engine clearance over the big rocks as I very rarely felt the sump hitting anything.

As I came to a very slow, technical part the engine stalled. This happened a few more times on the way down to the bottom of the gully and it was something I asked the technicians about as I wasn't sure how the idle worked due to the bike being fuel-injected. They pointed out it was easily solved with a small black knob tucked away which when turned controlled the idle speed of the engine like it would on a normal carburettor. After adjusting this I went back out for another lap of the track where I found the increased idle helped in the slower technical sections.

One of the most impressive things I found with this bike was that although it had a lot of power it was still a very quiet bike compared to most other enduro bikes even though it came fitted with Aprilia's new Akrapovic race system (available to buy as an optional extra). It's nice to see that a lack of noise doesn't have to mean the power's greatly affected.

Next was the moment I'd not been looking forward to too much - riding the 550. As I pulled away I was thinking this is going to be way too much of a bike for 90 per cent of off-road riders. Why do you need such a big engine when the 450 obviously has plenty of go in it?

Well it was a bit of a shocker but the engine was even softer than the 450 but still pulled and pulled with ease. The power just seemed to be more linear which made it easier to use. As you'd expect they both seemed similar to ride as they're both based on the same chassis - even the weight felt similar as the crank inertia didn't make much difference on the flowing terrain.

The 550 almost seemed easier to ride if anything as I felt more comfortable stood up on the pegs at high speed. I think this was because the handlebars were rolled slightly further forward so accommodated a standing position better.

It was only later in the day when riding the bike around a tight, wet, grassy test track that I realised the 550 was a bigger bike to throw around. It pushed a lot more in the slippery corners on the front end and felt heavier than its smaller brother while cornering.

Generally the bikes are a very good package and only small niggly things annoyed me such as the kill switch which was easily hit. Once pushed it acted like a master cut-out switch which meant that you had to push the button again before the electric start would work. I reckon a normal kill switch would be much better but I think Aprilia may have done this with rallye raid homologation rules in mind.

The second problem I found with these bikes was when I attempted to ride back up the technical gully we had come down. I found the bikes easily overheated when I had to get off and push over certain obstacles. As I was waiting for the bikes to cool down I checked out the radiators. Although they're very large there was no fan - something I think is important on large four-strokes in technical sections as no matter how big the radiators are if there's no flow of air they don't cool the coolant. This is another point I bought up with the technicians. I was told that there was a fan included in the extras kit - it just hadn't been fitted.

While I was pushing the 550 up the ravine I had another thought. Unless your name is David Knight or Chris Tett, for hard technical events I reckon big thumpers - whatever the marque - are best left alone. I personally feel the 550 is well suited to fast flowing hare scramble type events, rallyes and for trail riding where it can be used to its full potential. That is unless you enjoy pushing big thumpers up the sides of mountains. Personally, that's not for me...

Specs - Aprilia RXV 4.5

Capacity: 449cc

Bore and stroke: 76mm x 49.5mm

Transmission: Five-speed

Fuel system: Electronic fuel injection with 38mm throttle body

Front suspension: Marzocchi 45mm USD fork

Rear suspension: Sachs shock

Front brake: 270mm disc

Rear brake: 240mm disc

Wheelbase: 1495mm

Seat height: 996mm

Specs - Aprilia RXV 5.5

Capacity: 549cc

Bore and stroke: 80mm x 55mm