Front Crankshaft Ball Bearing for GT55, GT60 — O.S. Engine OS29730000  [OS29730000]

GT55/GT60 front crankshaft bearing overview

This is a front-position replacement bearing for the crankshaft on the GT55 and GT60 O.S. engine models referenced in the product title. It supports the crank spindle at the front end and reduces friction to maintain smooth rotational operation under normal conditions.

Fitment is limited to the GT55 and GT60 models specified in the product name, so confirm your engine model before purchasing. The bearing is installed as a mechanical press-fit into the crankcase front plate; use a proper bearing press or a soft-faced driver to avoid damaging the bearing race or crankcase. You may need to remove the carburetor and cooling head to access the crankshaft for replacement.

When tuning or investigating engine response problems, inspect the bearing for roughness, axial play, or excessive endfloat because a degraded front bearing can create vibration that affects idle quality and throttle response. After installation, check free rotation by hand and perform a short low-throttle running check to ensure correct seating.