The OS Engines Speed R2106 on-road engine, which has further evolved as the flagship engine that O.S. is proud of, has improved the output characteristics in the mid-speed range by reviewing the shape of the 9-port cylinder. The cylinder liner adopts a new shape of 9 ports, and the port shape has been revised to improve power in the mid-speed range. The crankshaft uses the well-established EURO2, and in combination with a rear bearing that uses ceramic balls, it achieves an improved feeling from low speeds. In addition, the connecting rod has been changed to a reinforced type. The carburettor has been revised to make it easier to adjust in the racing scene.