YS Engine YSS1001 50ST Crankcase Replacement for 50ST Engines  [YSS1001]

50ST Crankcase Replacement and Compatibility Notes

This crankcase is the replacement casing listed as YS ENGINE CRANKCASE 50ST #S1001 and is intended for use on the 50ST engine family in RC models. The paragraphs that follow address compatibility verification, inspection points, and assembly guidance.

Use this crankcase when restoring or servicing the lower engine assembly. It secures internal rotating assemblies and provides mounting interfaces for external fittings; always cross-check your engine serial number and consult the service manual to confirm fitment prior to installation.

This replacement crankcase is intended to bring a worn or damaged case back to serviceable condition, restoring alignment and mounting accuracy for dependable operation of YS 50ST-series engines.