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

Front bearing for the GT55 & GT60 crankshaft

This component is a direct replacement intended for the front crankshaft location of the GT55 and GT60 O.S. engine variants named in the product title. Its purpose is to support the crank spindle and minimise friction at the front end to maintain smooth rotational behavior under typical running conditions.

Compatibility is confined to the GT55 and GT60 models shown in the product name, so check your engine code prior to purchase. The bearing is fitted by pressing into the crankcase front plate; employ a bearing press or a soft-headed driver to avoid damage to the crankcase or bearing race. You may need to remove the carburetor and cooling head to access the crankshaft for replacement.

During tuning or when troubleshooting engine response, examine the bearing for roughness, axial play, or excessive endfloat. A worn front bearing can introduce vibration that undermines idle stability and throttle response. After installation, ensure the crank turns freely by hand and conduct a short low-throttle run to confirm proper seating.