Aprilia RS250 - the LAST fire-breathing two-stroke roadster
By Mike Hanlon
June 4, 2004
It's the closest thing you'll find to a genuine Grand Prix racing machine on the road, be it two wheels or four. The Aprilia RS250's 250cc two-stroke motor produces in excess of 60 brake horses, giving it a specific output of 240 bhp per litre - more than the fastest MotoGP bikes and on a par with F1 engines. And it's the last one - the fire-breathing two-stroke racer-roadster is about to become extinct. The next batch of Aprilia RS250 road bikes will be the last. Ever!!!!
Around 40 years ago, the two-stroke engine came into its heyday. Two-stroke engines were cheap to manufacture, the mysteries of reliability and metallurgy had been solved and they produced exceptional performance in comparison to four-strokes of equivalent capacity.
Yamaha, Suzuki and Kawasaki sold thousands of 250 two-strokes based around their very similar and successful two-stroke racing machines, and many of the biggest names in motorcycle sport got their start in the 250 production racing class.
In Grand Prix racing, the two-stroke quickly became unbeatable. Producing an unreliable 50bhp in the sixties, the development of the two-stroke racing motorcycle continued at breakneck speed for four decades, with the top racing 250s of today producing more than 100bhp. If your liter sportsbike produced as much power per cubic centimetre of swept volume, your right hand would be controlling (maybe), 400 hp.
Throughout the sixties the wail of expansion chambers slowly but surely banished the roar of four-stroke racing machinery at world championship level, at first in the smaller classes, and eventually in all classes.
Once Yamaha worked out that it could put two 250 twins together and make a four-cylinder 500, the writing was on the wall. Jarno Saarinen scored the first win in the premier-class by a four-cylinder two-stroke machine in May 1973, and Giacomo Agostini rode to the last four-stroke machine to victory (prior to the current MotoGP era), at the Nurburgring in August 1976. It was the end of the four-stroke era, the last victory by MV Agusta and the last time the world's most successful motorcycle racer ever stood on the top of the podium.
Aprilia didn't enter racing until the late eighties, winning its first GP in 1987, its first 125 title in 1992 and its first 250 title in the hands of Max Biaggi in 1994 and since that time the majority of bikes on the 125 and 250 World Championship grids have been produced by Aprilia. The need for harsher emission standards for road-going machinery was having an opposite effect on the two-stroke's success on the road however.
The last 250 two-stroke manufacturer of road bikes in Japan was Suzuki and Aprilia has been using the Suzuki v-twin 250 two-stroke motor as the heart of its RS250 roadster since then. With Suzuki ceasing production, Aprilia no longer has a supply of motors and is running out its road bike RS250 models and the 2004 model will be the last - the very last example of a breed of motorcycle which will hold a special place in the heart of motorcycle enthusiasts forever.
In 2003, Aprilia's 250 race bikes won 14 of the 16 world championship races, with five different Aprilia riders standing atop the podium. Significantly, the speed traps often showed the fastest ten riders were all Aprilia mounted. Not surprisingly, the roadster bears a very strong visual relationship to Aprilia works racing bikes which won the World 250 title last year in the hands of Manual Poggiali.
And riding it was a HOOT!
At low engine speeds, it has less power than a 125 scooter, and even when the revs climb past 5000 rpm, the engine is still clearing its throat, but pedal the gearbox to keep the revs above 8000rpm, and it is one of the most thrilling experiences you'll have on two wheels.
Though the two-stroke 90-degree V twin engine may have originated from Suzuki, it is Aprilia's knowledge of the induction and exhaust cycles which give the RS250 the edge over the same motor in its last guise as a Suzuki. Actually, an edge is too much of an understatement.
For the last few years the Aprilia 250 has won every production race at the Australian titles and in some years has scored every POINT - i.e. it took all 15 point scoring places at all rounds of the title. There are almost as many changes to the motor than bits you'd recognise as Suzuki, with the resultant unit having the finest credentials ever to grace a 250 two-stroke roadster.
Funnily enough, while the motor kicks like a mule once the revs climb over 8000rpm, it is not the motor that is most likely to catch the RS250 rider out - it's the brakes.
With a dry weight of 140 kilograms and two 298 mm diameter floating disks on the front wheel, with two Brembo twin-piston callipres on each (with four differentiated diameter pistons), the front brake has more power than you'd have thought possible. Though it has loads of feel, it warrants immense respect because once you've become comfortable with the RS around the roads, you'll find yourself getting into corners with the back wheel OFF THE GROUND!!!
If you like the idea of backing a road bike into corners this is the bike you can do it on. Alongside a Buell, this is the easiest bike we've ever ridden upon which to perform very impressive stoppies (getting the back wheel waaay off the ground under brakes). Given the rear wheel's tenuous relationship to the tarmac under rapid deceleration, the 220 mm diameter twin-piston rear brake has been toned down to make it very gentle and progressive.
In some markets, the RS250, by virtue of its small 250cc motor, is classified as a learner's bike. That's just SO wrong! A learner rider throwing a leg over the RS250 is a recipe for disaster.
Just the same, the 60 horsepower motor and its 220 kmh top speed are the most impressive aspect for experienced riders - that's almost certainly the chassis and suspension set-up, which offers a precision unmatched by anything road-registerable on two wheels.
So precise is the steering that it feels like you can claim any spot on the road just by willing the machine over it, regardless of the speed or camber of the bend.
The handling is awesome, and it is a roadbike, and it can be ridden on the roads every day without the motor filling up with gunk, but the road is just not its natural habitat. The RS250 is a racer first and a roadster second.
Though it has pillion pegs, don't even think about trying to carry a pillion unless there's absolutely no alternative - it's painfully uncomfortable for both, the bike is unbalanced and walking might be a better solution.
The RS250 is ideally something to buy to put in the garage and stay there except for track days. It is a motorcycle to be oggled for its craftsmanship - next time you get near one of these babies, take a bit of time to check out the swinging-arm, the effort that has gone into wrapping those expansion chambers around the motorcycle so NOTHING scrapes (this is a motorcycle upon which you'll get your knee on the ground before something else touches), and just behold the attention to detail, all the way down to the race computer with adjustable redline and lap timing which nestles inside the fairing.
It is the finest example of a breed of motorcycle which is about to become extinct. It is also the final example - the point at which evolution stopped after 50 years of refinement and development of the roadgoing two-stroke.
I think I'll go and have a good cry!!!!