YS Engine YSF7309 Cylinder Head Screws for FZ110S  [YSF7309]

Heavy-duty replacement screws for FZ110S engines

This fastener set is produced for the YS Engine FZ110S series and carries the part number YSF7309. It is intended to replace lost or worn screws that secure the cylinder head to the crankcase on glow engines used in scale RC models.

Use these when routine inspection shows wear, corrosion, or missing hardware. Clean mating surfaces and check thread engagement before fitting. Begin threads by hand to prevent cross-threading, then tighten in stages to ensure the head seats uniformly. Excessive torque can damage crankcase threads or distort gasket faces, so proceed carefully.

For heavy use or frequent heat cycling, reliable head fasteners help maintain sealing and compression under load. Consider a small amount of removable thread locker if vibration loosening has been observed, but never substitute thread locker for proper thread condition.