Aprilia’s stunning GP four-stroke triple goes public

Published: 02 December 2001

PICK your jaws off the floor – Aprilia’s gorgeous new four-stroke GP bike uses a British-developed 990cc, 220bhp inline triple with pneumatic valves. And something not too dissimilar could be in YOUR garage in a few years’ time.

Aprilia finally unveiled its much-anticipated entry for next year’s MotoGP class at the Bologna Show. And boss Ivano Beggio told MCN the ideas honed on this bike will one day extend across the whole range. He said: " MotoGP will represent a test bed more relevant to our standard products, to which we can then apply many of the solutions adopted on our race bikes.

" This is a challenge which a company such as Aprilia, with racing in its blood, could not refuse. This bike represents our passion, our winning experience, our technology and even our dreams. "

The three-cylinder layout came as a shock to many, who presumed Aprilia would stick with the V-twin format the firm has fine-tuned in the RSV Mille.

But it chose the triple to take advantage of rules in 2002’s new GP class, which will give three-cylinder bikes a 10kg weight benefit against rivals like Honda’s new V5, Suzuki’s V4 and the inline four-cylinder Yamaha M1.

Aprilia claims a power figure of " over 200bhp " , but MCN has learnt the motor is already making 220bhp at 15,000rpm.

The pneumatic valve technology it uses, which is common in Fomula One race cars, works by using pressurised air to close the valves as opposed to the more conventional spring. One of the big advantages of pneumatic valves is that they eliminate valve bounce. A major reason for Aprilia’s decision to tackle this kind of technology lies with the firm behind the engine’s development – Cosworth Racing. It is well known for its F1 engines, and has a long relationship with Aprilia, having worked on the RSV V-twin.

In a similar fashion to Sauber, which developed the 990cc engine for Carl Fogarty’s Petronas World Superbike, Cosworth effectively used three cylinders from a three-litre V10 F1 motor as the basis for the engine – it is no coincidence both opted for triples.

Another piece of F1 technology that has made it onto the Aprilia is a " ride-by-wire " throttle control. The throttle is not connected to the fuel injector system by a cable but instead an engine management system interprets the movement and sends an electric signal to servos, which operate the injectors.

The rest of the motor is pretty standard. It uses four valves per cylinder, forced lubrication and dry crankcases. Also likely is the motor has a " super sucker " pump. This sucks unwanted power sapping air and oil out of the engine and into a separate area where it is recycled back into the motor.

The engine block is made of alloy as are the head and cylinders. As the cam cover is subjected to little strain it has been made of carbon fibre to save extra weight.

The gearbox is six-speed and is completely removable to speed up changes of gear ratios during practice.

The advantages of this is that the throttle control no longer needs to be linear, which you get with a cable, but can be altered to suit the rider. Small throttle openings can be tuned to give either large amounts of power or very little, giving the rider far more control over the bike’s acceleration. Because the whole system is controlled by computer it can also be tailored to suit individual tracks.

The fuel injection system appears to rely on a single injector per cylinder however it is possible there is a second and even a third injector in the buried inside the injector body. Ignition coils are hidden under the cam cover with a single electrical connector at the left hand side of the case all that is showing.

The two exhaust pipes per cylinder format breaks with the current convention that one large pipe is better but there is a school of thought that dirty air tends to cling to the side of big bore exhaust pipes slowing down the exiting gas and reducing power. The other GP bikes from Honda and Suzuki have stuck with single pipe technology.

An aluminium dual beam frame, like the RSV’s, houses the new motor and appears similar to the superbike racers. Aprilia has given themselves two options with the swingarm. One is a more conventional aluminium unit and the other a carbon fibre one. The design varies between them and they can be interchanged depending on the track.

Forks are 42mm Ohlins, like the WSB and GP bikes, and the shock is also Ohlins. Brakes are radially mounted Brembo calipers with carbon discs in either 320 or 290mm with the rear 218mm disc.

The wheels follow the GP convention of using a 16.5-inch rear and like the swingarm are made of either carbon or alloy.

The triple make sense from an engineering point of view because Cosworth could make its current F1 expertise bear immediately – but there could be another reason.

In July last year Aprilia took over Laverda when it was on the brink of going bust. Since then it has done very little with the company apart from launching a new scooter.

If Aprilia is looking to put the technology it learns from GP racing into production bikes the obvious route for it would be through the Laverda brand, which has a long history associated with inline triples, starting with a 900cc in 1973 and going through to a 981cc triple in 1982 and on with a1000cc up until it ran into financial difficulties in 1988 and was working on a brand new triple superbike when Aprilia took over.

Aprilia doesn’t have such strong ties with any engine format, unlike Ducati with the V-twin, and so can afford to be flexible with its motors. However its recent signing of Noriyuki Haga to a one man team in WSB shows the manufacturer is still very determined to win the title and is not looking like abandoning the RSV Mille.

Aprilia has not commented on when the bike is likely to first race, however it is believed that the project is behind schedule and a mid season entry is likely. The rider is also unknown however but following a imminent test with development rider Marcellino Lucchi, Aprilia has scheduled a test in January with the to be confirmed works rider.