YS Engine YSF1216 Replacement Rocker Arm Shaft Screw for 120/140 Engines  [YSF1216]

Replacement screw for 120/140 model engines

The YS Engine YSF1216 is a rocker arm shaft screw supplied for 120 and 140 class RC engines, and is intended as a direct replacement during routine engine servicing. The item secures the rocker arm shaft and aids in maintaining accurate valve linkage alignment while engines are serviced or rebuilt.

In normal use the screw fixes the rocker arm shaft so the rocker arms can transmit motion from the cam and valve mechanism into the valve train. Inspect the thread condition, screw head profile, and check for corrosion before deciding to reuse the part; any damage that could impair secure fastening should prompt replacement.

Fitment guidance: fit the screw so the rocker arm shaft runs without side load, ensure smooth rocker motion after tightening, and verify clearances during initial run-in. This component is intended for maintenance and exact fit rather than as a performance upgrade.