I rode an Aprilia 50cc scooter, equipped with the Orbital DFI Combustion Process, several years ago, and can testify to how different it was. First, upon starting, the engine idles as smoothly and steadily as a four-stroke. As you ride away, the engine continues to fire regularly. Why? When a simple two-stroke idles, a very small volume of fresh charge mixes with a cylinder fulll of exhaust gas. The usual result is a misfire. But after one or two more cycles, enough fresh charge accumulates in the cylinder that the spark plug is finally able to ignite it. So the result is an irregular series of firings with one or more misfires between—the classic "ring-ding idle." As the rider begins to open the throttle, more fresh charge is admitted, so the engine misfires less often, at first eight-stroking, then four-stroking, and finally, at about 30 percent throttle, firing smoothly all the time.