O.S. Engine OS21656000 Piston Pin Replacement for 12XZ 12TG 12TZ  [OS21656000]

Wrist pin duties and installation fit

This piston pin is offered as an RC engine replacement intended for the O.S. Engine 12XZ, 12TG, and 12TZ model designations listed in the product name. It secures the piston to the connecting rod and ensures correct alignment during combustion, contributing to steady piston movement and repeatable compression behavior.

Installation notes: inspect the wrist pin bore and the rod small end for wear prior to fitting, keep all mating surfaces clean, and adhere to your engine manual for lubrication and proper assembly order. During a rebuild some minor fitting is normal; retain the pin using the circlip or the retention technique advised for your engine model.

Maintenance advice: the pin does not change compression or timing, but correct fit and condition are critical for consistent running. Replace the pin during top-end service if you find scoring, deformation, or excessive play to avoid further damage to piston or cylinder.