O.S. Speed R2105 Combo Set Car EngineThe O. S. SPEED R21 series won the previous World Championships held in the United States. With the new 'R2105' series, most of the parts have been designed from new to aim for consecutive victories at the world championship to be held in Japan this year. To increase torque on high grip track surfaces, a newly designed 9 port sleeve has been adopted. O. S. SPEED's traditional DLC coated crankshaft delivers linear power from low to top end by changing