The updated version of the Kawasaki Ninja 250 along with the recent spike in gas prices has brought a resurgence to the small-bore motorcycle market. Ever ones to jump on the little bike bandwagon, for 2009 Aprilia is bringing its RS125 two-stroke here to the states. One caveat: it's not road legal, meaning that if you want to spend the $5499 it takes to get one then you're probably not hurting too badly from this economic downturn. But back to the bike; design cues come directly from its grand prix racing cousins, even down to the "Spain's No. 1" livery that graced Jorge Lorenzo's 250cc championship-winning machine in 2007. Power comes from a single-cylinder, liquid-cooled 125cc two-stroke engine with a separate lubrication system (meaning no premixing of the fuel and oil). Bringing the bike to a halt is a single 320mm rotor clamped by a four-piston, radially-mounted caliper.
While not legal for road use in the states, these little flyers are rampant in Europe due to the tiered licensing system they use. As such, the RS125 makes some concessions to meet the demands of street riders, while keeping as much of the racing heritage as it can. For instance, the bike has an electric starter. The front fork is an inverted unit with no adjustability, and the rear shock is only preload adjustable.
That said, it's much closer to a true racebike than the Ninja 250 will ever be. Both make about the same power (albeit in much different fashions) and with a dry weight of just 280 pounds the Aprilia should have a distinct advantage in handling. We had the opportunity to sample the RS125 at a Fastrack Riders (www.fastrackriders.com) trackday at Willow Springs and the differences were immediately noticeable. Being a two-stroke, the 125 goes nowhere until the engine is spinning near redline. Only then can the clutch be feathered out. Once moving, the six-speed gearbox is smooth and positive. This is good because you'll be shifting often to keep the bike in its narrow powerband. The huge brakes are almost too much, but it never overpowers the rest of the machine. One finger braking is easy with the clamping force the four-piston caliper provides.
Flicking the bike from side to side is where the weight difference comes in handy. At the mere thought of direction change the RS125 will move where you want it to go. This weight advantage also helps in acceleration, as it gains speed quicker down the front straight than the Kawasaki. The suspension, while basic, performs admirably. The damping rates are geared more towards street riding (meaning soft), but provide adequate compliance on the track.
Overall, the Aprilia RS125 makes a very competent (and fun) track toy. But that's all it will ever be. It's not street legal here and there are no racing classes for it. Besides, if two-stroke racing is something you'd like to try then a true, dedicated racebike will suit your needs better.