Genuine OS factory piston pin (gudgeon pin) for the FS-56α (FS-56A) four-stroke glow engine. The pin is the hardened, precision-ground shaft linking piston to connecting rod — small, simple, and critical, since all of the engine's power passes through it.

This pin comes complete with white end pads fitted at both ends. In place of wire circlips, the soft pads allow the pin to float in the piston while protecting the cylinder bore — there are no separate retaining clips to fit or lose. Inspect the pads when reusing a pin; if they're worn, gouged, or missing, fit a new pin.

Replace the pin whenever it shows visible wear marks, scoring, or discolouration from heat, and inspect it as a matter of course during any top-end rebuild — a worn pin accelerates wear in both the piston bosses and the rod's small end. If the engine has suffered a hydraulic lock or prop strike, check the pin alongside the rod, as bending loads pass through both. Handle and fit with bearing-surface cleanliness, with a wipe of fresh fuel or after-run oil before assembly.

Specifications

Brand: OS Engines (Japan)
Part number: 44606000
Type: Piston pin (gudgeon pin), floating, with end pads fitted
Suits: OS FS-56α (FS-56A) four-stroke