O.S. Engine OS49403200 Precision Piston for GF40 Engines  [OS49403200]

Overview: GF40 piston service considerations

The OS49403200 piston fits GF40-series cylinders and is listed under model OS49403200 for replacement use. This summary explains fitment checks, how piston condition can influence engine behavior, and key service procedures for hobbyists.

This piston is intended for GF40-design engines and compatible cylinder kits. Before fitting, inspect the cylinder bore, confirm that piston rings operate freely in their groove, and verify piston-to-wall clearance per service limits. Because the piston is a wearable part, correct installation and ring condition are vital for steady compression and predictable throttle response.

In maintenance work, remove the cylinder head to inspect mating surfaces, check ring movement, and then carry out a measured run-in while observing operating temperature and compression. For precise fitment advice or to source spare items, consult the official O.S. Engine parts list or an authorised dealer.

This piston is a direct replacement for GF40 engines; follow inspection and assembly guidance to maintain consistent engine tuning and reliability.