作動ピストン

A piston is the cylindrical part that moves up and down inside an engine cylinder to transmit combustion force.

Burning fuel pushes the piston down, and the connecting rod turns this motion into rotation of the crankshaft; rings on the piston seal the combustion gases and control the oil.

Pistons run inside the cylinder liners of the engine, one per cylinder. The correct piston matches the engine model, bore size, and ring set.