Engine Sleeve 105HZ Service Part OS28703100 by O.S. Engine  [OS28703100]

Overview of the 105HZ replacement sleeve

This replacement sleeve, model OS28703100 from O.S. Engine, is designed as the wear surface for the piston in RC engine rebuilds. It restores compression and smooth running when the original bore shows wear.

Prior to fitting, inspect the crankcase mating bore for damage and check the piston for correct diameter and skirt condition. Clean mating surfaces thoroughly, remove any imperfections, and ensure the sleeve aligns concentrically in the case to avoid sealing distortion.

Apply a light, heat-resistant lubricant to the bore and piston for the initial run-in period. Adopt a careful break-in approach: monitor engine temperature and running characteristics, and make small tuning changes to carburation and ignition only after confirming the liner has seated.

During maintenance checks look for loss of bore finish, corrosion pitting, or abnormal piston wear; replace the sleeve if bore integrity is compromised or running issues persist after tuning.

This sleeve is intended as a direct replacement during engine overhaul; careful fit and conservative break-in will protect the piston and connecting components.