Stroke of Genius

STROKE OF GENIUS

CW RIDING IMPRESSION

APRILIA'S STREET-GOING RS250 EMULATES THE FIRM'S GP MACHINERY. DOES IT PERFORM AS WELL AS IT LOOKS?

APRILIA'S BOSSES ARE A cocky, self-confident lot these days. They're full of smiles-and with good reason. They've hit upon a winning combination. First, Kazuto Sakata and Max Biaggi grab the 125 and 250 GP world titles for Aprilia; then the Italian firm launches the RS250, the nearest thing you’ll find to a grand prix machine on the street.

The bike's chassis is a copy of Biaggi’s 250 frame, the wheels and bodywork mimic Loris Reggiani's RSV400 (which made occasional forays into 500 GPs this year), and the liquidcooled, 90-degree, two-stroke V-Twin is a modified Suzuki RGV250 unit. The RS250 looks sensational in Reggiani colors, with its kicked-up tailsection, sculptured tank, fairing and seat unit, massive banana swingarm and tiny headlights. The no-nonsense design is enough to send a shiver down the spine of any race enthusiast. Indeed, one glance gets the adrenaline going.

Fortunately, the RS250's performance lives up to its appearance. At 311 pounds dry. the RS is the lightest bike in its class. Add to that a taut frame, phenomenal brakes and sticky tires, and you effectively have a pure racer with a few road-going necessities. At the bike's launch at the twisting Misano circuit in northern Italy, the RS excelled. Handling is superb. The tiny bike can be stuffed into bends, carry outrageous cornering speeds and brake right to the apex without upsetting its chassis. This may be the ultimate backroad scratchen

The polished, twin-beam aluminum frame is a slightly toned-down version of Biaggi’s. Whereas Biaggi would demand a twitchy head angle of around 23 degrees, the RS250’s rake is a more-conservative 25 degrees, with 4.0 inches of trail. The frame consists of a pressed and welded thin-wall shell structure, with reinforcing internal ribbing and cast aluminum and magnesium alloy engine mounting points. The massively-braced swingarm is of similar construction, with asymmetrical arms. The drive chain runs through an aperture in the left arm, while the right is banana-shaped to allow the twin exhaust pipes to exit and still give excellent ground clearance.

The 40mm inverted fork is multiadjustable. Twelve-position rebound adjustment is found on the right, while preload can be adjusted via a knob atop the left tube. There is no compression adjustment. The gas-charged Boge shock is fully adjustable.

A quick flick of the clip-on handlebars is all that’s needed to turn this agile Aprilia. It steers accurately and manages mid-corner directional changes with aplomb, flip-flopping through Misano's esses in a flash. That’s partly thanks to the five-spoked aluminum alloy wheels, which are very light and hold gyroscopic effects to a minimum. Aprilia claims a 10-percent reduction in inertia over any other production bike wheels.

Pirelli Dragon tires come standard, and despite constant thrashing, the front 110/70-17 showed minimal wear. The rear 150/60-17, however, wore rapidly, likely a reflection of the overly stiff shock spring. Initial movement is reasonably soft, but the second half of travel is much stiffer. Reducing compression damping only made the rear squat excessively when exiting slower corners.

Misano is a quick circuit with lots of hard braking points, perfect for testing the RS250's stoppers. The four-piston Brembo calipers and 1 1.4-inch twin front discs are extremely powerful and progressive. Initial bite can catch you off guard, though, as I found out when 1 braked very late and grabbed at the lever. Nonetheless, they were as powerful and sensitive at the end of each session as at the start. The rear brake consists of an 8.7-inch disc with a single-piston caliper, and was spongy with little power—perfect for track use.

Using Suzuki’s RGV250 engine was a bit of inspiration by Aprilia. Despite the Aprilia trademark stamped on the casings, the entire motor is manufactured in Japan. It's a competent unit, upgraded with some fine-tuning by the Italians. The cylinder heads have an improved combustion chamber, with larger coolant ducts for better temperature control. The clutch case has been redesigned for increased oil circulation around the clutch plates. There's a marginal weight reduction on the left, with a smaller flywheel cover and a plastic pinion cover.

Significant work has gone into the exhaust, which was completely redesigned by Aprilia and manufactured by a outside supplier. In conjunction with the Aprilia-designed electronic control unit, the exhaust system is claimed to offer a higher top speed. 9 percent more peak power and reduced emissions. In regards to noise, the tiny, carbon-fiber silencers are largely ineffective, especially at full bore, although Aprilia says they fall within current leg-

islation. Aprilia claims 70 horsepower at I 1,500 rpm, with a compression ratio of 13.2:1.

Above 9000 rpm, the motor is responsive and very lively. Drop to 8000 rpm and the resultant waiting period seems never-ending, while the engine stops dead at its 12,000-rpm redline. With a mere 3000 rpm to play with, the slick, six-speed gearbox is in constant use. The ratios are too widelyspaced for track work, but should prove well-chosen for street use. Aprilia claims a top speed of 130 mph. At Misano, the RS topped out at an indicated 124 mph in fifth gear.

On the track, where you’re constantly moving around the machine, the RS250 feels instantly comfortable. Its alloy bars are quickly adjustable, and seat padding, though minimal, should be satisfactory for street use. The Honda-style switches are well-positioned. while the mirrors are practically useless.

How long does it take to blast down to the local corner store, buy a quart of milk and race home again? Aprilia’s on-board computer will reveal all. The digital screen-located between the easily read speedometer and tachometer-displays engine temperature, battery charge, time and lap times. The lap timer is operated by your left-hand forefinger and will display each lap time for 15 seconds while timing the following circuit. It will also memorize up to 10 laps and recall them at the end of your session.

Aprilia will produce 3500 machines this year. In Britain, the RS250 will retail for the equivalent of $9200, which meant cutting a few corners, the most obvious being the absence of lacquer over the decals. Still, the RS250 has that unique Italian flair.

Ducati may have won the World Superbike title this year with its 916, but in the battle for the hottest roadgoing race replica, there is no contest.

-Olly Duke