Single cylinder water cooled 4 stroke, 4 titanium radial valve.Bore x stroke are 79 mm x 50.9 mm respectively, total displacement is 249.5 cc.The transmission is a 6-speed constant meshing type, oil lubrication is a dry sump type and combined with an oil pump.This is a very unusual oil lubrication system in the current legal model (public road running model), adopting the same method as the racing engine used under severe conditions.With the Mikuni fuel injection system, the SM250R realizes not only a lightweight, compact yet high output but also very easy to use torque output characteristics.The 13% compact engine compared with the conventional model is very powerful and excellent in throttle response.