Ring gear assembly is to transfer the power to the starter connector of the crankshaft, the main role is to transfer power between the engine and the engine crankshaft is provided, the inertia flywheel is a large inertia rotating disc, mounted on the engine crankshaft flange on the outer edge of the flywheel is pressed on a ring gear can be meshed with the driving gear the starter, at the same time it is followed by a joint clutch.