O.S. Engine OS23930000 Crankshaft Ball Bearing for R 21RX, 21XM  [OS23930000]

Crankshaft ball bearing for model engines

This replacement crankshaft ball bearing is an RC-scale accessory intended for use with O.S. Engine R 21RX and 21XM engine variants as listed in the product name. It serves the specific role of supporting crankshaft rotation, reducing friction, and keeping shaft alignment stable during throttle changes and running loads on model engines.

Installation notes: inspect the crankcase and bearing seats for burrs or contamination before pressing the bearing into place, use a proper bearing driver or an even press fit tool to avoid bearing damage, and check endplay and free rotation after installation. For maintenance, verify bearing smoothness and replace if any roughness or play is detected.

A focused replacement part for model engine rebuilds and routine maintenance, this bearing is used where original bearing fit and crank alignment are required to restore engine performance.