4 Pcs Motorcycle Engine Parts STD Bore Size 56mm Piston Ring For RF400 GK78A RF 400 78A This set includes four piston rings designed for motorcycle engines with a standard bore size of 56mm.The rings are compatible with engine models RF400, GK78A, RF 400, and 78A.These replacement parts are engineered to maintain proper compression and oil control within the engine cylinder.Each ring is constructed to meet specifications for fit and function.The package contains four identical piston rings suitable for use during engine maintenance or rebuilds. Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.