FZ110S Cylinder Head Screws YSF7309 - YS Engine  [YSF7309]

Installation guide for FZ110S head screws

This replacement fastener set is intended for the YS Engine FZ110S glow engine family and is listed under part code YSF7309. The kit restores the mechanical connection between the cylinder head and the crankcase on model glow engines.

Fit these screws when worn or missing hardware is found during regular engine service. Inspect mating faces and threads for contamination or damage before fitting. Hand-start each screw, then tighten progressively in a crisscross pattern to seat the head evenly. Avoid over-torquing to prevent damage to crankcase threads or head gasket surfaces.

During tuning and high-RPM running, correctly fitted head fasteners support consistent sealing and compression through heat cycles. A light application of a removable thread locker can help if vibration loosening is a concern, but do not use thread locker to mask damaged threads.