F120 Back Plate Screw Replacement YSF1231 for YS Engine  [YSF1231]

F120 Rear Cover Fastener

This YS Engine back plate screw is a direct spare for the F120 back plate assembly used in scale RC glow engines, supplied under model YSF1231. It serves as the mounting fastener that secures the engine's rear cover to the crankcase and is intended as a service replacement when original fasteners are worn, stripped, or missing.

Installation notes: thread the screw into the back plate boss until seated with a firm, even torque to avoid cross-threading; if resistance is abnormal stop and inspect the mating thread. The design purpose is mechanical retention rather than tuning, so use it to restore correct assembly and sealing of the back plate.

Compatibility: the product name indicates fit for F120 back plate applications; confirm part YSF1231 matches your engine's back plate layout before ordering. This part supports routine maintenance cycles and quick replacement during bench servicing or track-side repairs.