Aprilia RS 250

What is the Aprilia RS 250?

Aprilia’s corporate history places the RS 250’s road-bike debut in 1995. It’s a compact, fully faired two-stroke built around a 90-degree V-twin and an aluminium twin-beam chassis, and visually it sits close enough to Aprilia’s racing world to look like a miniature Grand Prix machine. That resemblance only takes you so far, though: the figures here are for the 1998 European road motorcycle, which Aprilia’s own workshop literature identifies separately as Model 1998.

The RS 250 changed enough during its life that the year matters before the numbers do. For 1998 Aprilia changed the front fork and axle, widened the front rim and tyre, revised the front-brake hardware, added a digital display with a programmable shift light, fitted an aluminium rear subframe and altered the exhaust and catalyst. Earlier road bikes therefore carry different dimensions, fuel capacity, front-wheel hardware and mass.

The U.S. RS 250 Challenge, Aprilia’s pure 250cc Grand Prix racers and the much later RS 250 SP are separate machines. The Challenge was sold as a race motorcycle in the United States, while the 2019 RS 250 SP was a new track-only Sport Production project developed for a different era.

The 1998 road revision

Aprilia’s 1998 handbook gives the revised road bike a 1,975 mm overall length, 690 mm width, 1,180 mm height to the front of the fairing, an 810 mm seat height and a 1,360 mm wheelbase. Ground clearance is listed at 135 mm. Aprilia’s workshop catalogue identifies this revised phase separately as Model 1998.

Period testing makes the hardware changes easy to see. MOTORRAD described the 1998 bike as gaining a stiffer 41 mm fork with a 25 mm front axle, revised Brembo front callipers and master cylinder, a 3.5-inch front rim with a 120/60 ZR17 tyre, an aluminium rear subframe and a new digital instrument display. The magazine contrasted those parts directly with the 1997 motorcycle’s 40 mm fork, 20 mm axle, 3.0-inch front rim and 110/70 front tyre.

That makes model year more useful than livery when identifying an original bike. Replica colours and sponsor graphics can be important to an individual motorcycle, but paint alone does not establish a different mechanical specification.

Suzuki engine, Aprilia development

The 1998 RS 250 uses a liquid-cooled, two-cylinder, 90-degree V-twin two-stroke displacing 249.25 cc from a 56 mm bore and 50.6 mm stroke. Aprilia’s handbook gives a 12 ± 0.7:1 compression ratio, reed-type intake, an exhaust-port valve and separate lubrication through a variable automatic oil mixer. The engine is kick-started rather than electric-started.

Its origins are Suzuki rather than an Aprilia Grand Prix engine. At the 1995 production launch, Cycle World described the complete motor as manufactured in Japan and based on the Suzuki RGV250 unit, with Aprilia making its own changes around combustion, cooling, clutch-case oil circulation, exhaust and electronic control. By 1998 MOTORRAD still described the road engine as derived from Suzuki’s RGV 250.

Power figures vary by period and configuration. Cycle World quoted Aprilia at 70 horsepower for the early 1995 road bike. MOTORRAD’s 1998 test reported 61 PS from the revised motorcycle while also noting that the brochure listed 55 PS, a discrepancy the magazine said it could not explain. Aprilia’s 1998 handbook gives no torque figure.

Carburettors, gearbox and oiling

Fuel is metered by two Mikuni TM34 carburettors. The 1998 handbook describes a separate oil-pump circuit feeding the variable automatic mixer at 0.9 to 2 per cent, with liquid cooling by pump. The mixer-oil tank holds 1.6 litres including a 0.3-litre reserve; transmission-oil capacity is 700 cc.

Transmission is a six-speed mechanical gearbox with a wet multiplate clutch and left-side foot control. Aprilia lists a 23/59 primary reduction and individual gear pairs of 11/27, 16/26, 17/21, 22/23, 24/22 and 25/21. Final drive is by chain. The same handbook presents 14/42 and a parenthetical 14/43 final sprocket option; the available version information does not show which market receives each pair.

The narrow, peaky character remained part of the experience, but the 1998 exhaust and catalyst revisions improved road manners. MOTORRAD found the revised engine usable from around 3,000 rpm and much stronger in the midrange once it passed roughly 7,000 rpm.

Aluminium chassis, suspension and brakes

The frame is an aluminium twin-beam structure using cast and stamped elements. For the 1998 road bike Aprilia specifies a 25°30′ steering-head angle, 102 mm of trail and the 1,360 mm wheelbase. The asymmetric aluminium swingarm leaves clearance for the twin exhaust routing that became one of the RS 250’s visual signatures.

The front suspension is an adjustable upside-down fork with 120 mm of travel; period testing identifies the revised 1998 unit as 41 mm. The rear uses an adjustable hydraulic monoshock. Aprilia gives 64 mm for the shock absorber’s own stroke, which is not the same measurement as rear-wheel travel.

Braking is by twin 298 mm front discs and a single 220 mm rear disc. MOTORRAD’s 1998 road test identifies the revised front hardware as Brembo and praised the new master cylinder and callipers for more precise control than the previous version.

Wheels, tyres, fuel and mass

Aprilia’s 1998 handbook lists light-alloy wheels measuring 3.5 x 17 inches at the front and 4.5 x 17 at the rear. The corresponding road tyre sizes are 120/60 ZR17 front and 150/60 ZR17 rear. MOTORRAD described its 1998 test bike with a 160/60 rear in its change list; the factory handbook lists 150/60 for the road motorcycle.

Fuel capacity is 19.5 litres including a 3.6-litre mechanical reserve. The handbook’s mass figure is 167 kg ‘ready for starting’. MOTORRAD independently described its test bike as 162 kg fully fuelled; the two figures use different sources and conditions.

The earlier road phase used different values in several of these areas, including a smaller front rim and tyre and a smaller fuel tank. An original RS 250 should therefore be identified by production phase before a specification list is used to judge whether its equipment is correct.

What period testing found

Werner Koch tested the revised European road motorcycle for MOTORRAD in February 1998. The article found the wider-front-tyre bike stable through Hockenheim’s uneven sections, with strong feedback from the adjustable suspension and no obvious loss of agility from the wider front wheel.

The engine’s stronger midrange also made the widely spaced first three gearbox ratios easier to live with, although the magazine still described the six-speed shift as slightly notchy. The revised front brake hardware was praised for sharper, more controllable response. At the top end MOTORRAD reported that the test bike passed 200 km/h; the article did not present that as an Aprilia factory top-speed claim.

MOTORRAD also warned about the exhaust-valve mechanism and recommended the scheduled inspection regime. The warning concerned period maintenance; condition and maintenance history vary between surviving RS 250s.

Road bike, Challenge racer and Grand Prix machines

The European road RS 250 and the U.S. RS 250 Challenge share a name and core architecture, but their legal and equipment states are different. Aprilia’s Challenge service literature explicitly says the U.S. motorcycle was sold as a racing machine and was not legal for public-street use. Cycle World described the Challenge as losing the road bike’s lights and gaining fibreglass bodywork, braided brake lines, a steering damper, race-oriented suspension and pipes.

Aprilia’s 250cc Grand Prix racers are a different boundary again. Period U.S. coverage distinguished the RS road motor from Aprilia’s contemporary GP engine architecture. Aprilia’s Grand Prix machines were built to a different specification entirely.

The later RS 250 SP is a different motorcycle

Aprilia revived the RS 250 name in 2019 for the RS 250 SP, a track-only Sport Production project announced for the 2020 Italian championship and developed with Ohvale. It belongs to a different technical programme and period from the 1990s road two-stroke.

The later SP uses a modern four-stroke powertrain and different chassis, suspension and brakes. It is a different motorcycle despite the similar badge.

Buying and researching an original RS 250

If you’re looking at an RS 250 today, start with the exact production phase. A 1998 road bike can be checked against the wider 3.5-inch front rim, 120/60 front tyre, revised 41 mm fork, digital display with shift light and later brake hardware. Earlier road motorcycles use a different front-wheel package and instrumentation, while a U.S. Challenge machine may have been supplied without road equipment from new. The common ‘Mk2’ label isn’t Aprilia’s workshop terminology; the factory catalogue identifies the revised phase as Model 1998.

Use the handbook or workshop material that matches the bike in front of you, not a generic RS 250 specification copied across several years. A replica livery doesn’t prove a mechanical variant, and a Cup-prepared or track-modified motorcycle needs its non-standard parts separated from the original road specification before the comparison means anything.

The historic road RS 250 is no longer a current Aprilia production model. Aprilia’s current corporate history records its 1995 birth but does not give an exact final production year. For a surviving bike, service history, original equipment, road-registration status and present condition are more useful than a general reliability score or a headline used price.