YS Engine YSS1008 Precision Wrist Pin for 50ST and 56SR  [YSS1008]

Compact wrist pin for YS 50ST/56SR engines

This wrist pin is a replacement component for RC-scale engines listed under YS Engine service parts that include the 50ST and 56SR model identifiers. It sits between the piston and the connecting rod, acting as the axial pivot that allows piston movement inside the cylinder.

Install this part during routine engine servicing or a full rebuild when the original wrist pin shows wear, scoring, or excessive clearance. Because it is a critical moving part, inspect the piston small end and connecting rod bores for wear before fitting and follow the engine manufacturer's disassembly instructions.

Installation and tuning role

• Installation notes: remove the piston assembly following the engine manual, align piston and rod small end, slide the wrist pin home and secure using the engine's specified retaining method.
• Tuning role: a correctly sized wrist pin maintains piston alignment and reduces lateral play that can negatively affect compression stability and throttle response.
• Maintenance tip: check for lateral play and surface scoring during rebuilds and replace the pin if any sign of wear is present to prevent accelerated piston or rod damage.