Kohler — Cylinder Bore Honing
Repair & overhaul · crankcase
From a Kohler service manual covering: CH18, CH20, CH22, CH23, CH25, CH620, CH630, CH640, CH670, CH680, CH730, CH740…. Check it applies to your exact model before use.
Applies to: Kohler CH18, Kohler CH740
Before you start
- POWER-BORE cylinders cannot be resized or honed.
Procedure
- Lower hone into bore and after centering, adjust so stones contact cylinder wall.
- With lower edge of each stone even with lowest edge of bore, start drill and honing process. Move hone up and down while resizing.
- When bore is within 0.064 mm (0.0025 in.) of desired size, replace coarse stones with burnishing stones. Continue until within 0.013 mm (0.0005 in.) of desired size, then use finish stones (220-280 gr
- After resizing, check bore for roundness, taper, and size using inside micrometer, telescoping gauge, or bore gauge at top, middle, and bottom.
Tools required
- cylinder hone Amazon
- low speed drill press Amazon
- inside micrometer Amazon
- telescoping gauge Amazon
- bore gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- drill speed about 250 RPM and 60 strokes per minute
- crosshatch 23°-33° off horizontal
- 0.25 mm (0.010 in.) or 0.50 mm (0.020 in.) oversize
Full service-parts list: Kohler CH740 →
Source: Kohler service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.