On the Aprilia Scarabeo 500, a twist of the grip gives rein to a single-cylinder 460 cc engine—one of scootering’s largest—and thrusts the fairly hefty machine easily away from rest. Although the initial response is a bit soft, allowing well-co-coordinated Accord drivers to beat you off the line, the big single soon reaches its torque peak and begins to tow the Scarabeo with real urgency.