YS 91SR Replacement Back Plate for YS Engine YSS9116  [YSS9116]

YS 91SR rear cover component

The YS Engine YSS9116 back plate is a direct replacement intended for the 91SR engine. It provides the rear closure for the crankcase and is used when the original back plate is damaged or being upgraded during rebuilds.

Fitment is simple for anyone used to servicing small model engines: remove the rear screws, note gasket placement, and reinstall the back plate while keeping fasteners tightened evenly to maintain correct alignment. Adopt careful handling of small parts to avoid cross-threading or seal damage.

During tuning or overhaul, this back plate supports crankcase geometry and sealing; swapping a distorted back plate can improve mechanical symmetry and engine response. Always verify the YS 91SR assembly match before completing installation.