O.S. Engine OS22631020 Replacement Ball Bearing for 12CV-R, 15CV-RX, 12TR, CZ-11PS  [OS22631020]

Fitment bearing for the specified O.S. engine codes

This bearing is supplied as a replacement component for select O.S. Engine units: 12CV-R, 15CV-RX, 12TR, and CZ-11PS. It is intended to remove endplay and roughness caused by worn races, restoring smooth support for internal rotating parts.

Confirm compatibility by checking the engine's model imprint before fitting. Perform the swap on a clean bench, following the engine maker's disassembly sequence for head and crank removal. Press the new bearing squarely into the housing using tools that bear on the outer race only.

Take care to keep contaminants away from the bearing during installation, inspect sealing surfaces and the crank journal for damage, and verify free rotation and correct endplay after assembly. While the bearing does not alter timing, replacing a high-friction unit helps maintain consistent throttle response when tuning the engine.