Aprilia's 660-cc Bikes Could Shake Up a Segment Gone Stale The Aprilia RS 660 and Tuono 660 are feature-packed, stylish alternatives to the typical sport bike or streetfighter. Can they succeed against the predictable choices? By Chris Cantle Aprilia Aprilia has, in quick succession, launched two middleweight motorcycles with the potential to upend their respective segments. They share a brilliant and hard-revving 100-horsepower engine, and they enjoy similar upmarket suspensions and stiff, svelte aluminum frames. And each bike plunges into an absolutely stacked market, hoping to conquer with technology, premium feel, and Italian swagger. Do these pretty little Italians have enough muscle to make waves in an ocean of competition? We put the RS 660 and Tuono 660 to the test in the mountains above Los Angeles to find out.