50SX-H 46FX-H 46SF Piston Ring (OS25303400) for O.S. Engine  [OS25303400]

Service spare piston ring for the listed models

This component is supplied as a direct spare for the O.S. engine models identified in the product name. It is intended for use when worn rings are replaced during scheduled service or overhaul work.

Installation involves removing the cylinder head and sleeve to access the piston, then removing the old ring and fitting the new part with care. Maintain cleanliness and use the correct tools to avoid scoring the piston or cylinder wall and to protect the ring groove from damage.

Although replacing the piston ring does not alter piston or bore geometry, it restores sealing and helps return compression to predictable levels, which supports stable combustion behavior during tuning. Verify the installed ring end-gap and perform a controlled break-in before adjusting jetting or ignition settings.

Please ensure your engine model matches the codes listed in the product name (50SX-H, 46FX-H, 46SF) to confirm fitment.