Kohler — tidges. Check size frequently.

A Kohler service procedure — check it applies to your exact model before use.

Browse Kohler generators & specs →

Procedure

1. 3. When bore is within .0025” of desired size, re-
2. move coarse stones and replace with burnishing
3. stones. Continue with bumishing stones untit
4. within .0005” of desired size and then use finish
5. stones (220-280 grit) and polish to final size. A
6. crosshatch should be observed if honing is done
7. correctly. The crosshatch should intersect at ap-
8. proximately 23-33° off the horizontal. Too flat of
9. an angle could cause the rings to skip and wear
10. excessively, foo steep of an angle will result in
11. high oil consumption (refer to Figure 10-2).
12. Figure 10-2. Cylinder Bore Crosshatch After Honing.
13. 4. After resizing, check the bore for raundness, taper,
14. and size. Use an inside micrometer, telescoping
15. gauge, or bore gauge to take measurements (Re-
16. fer to Figure 10-3). The measurements should be
17. taken at three locations in the cylinder--at the top,
18. middle, and bottom. Two measurements should
19. be taken (perpendicular to each other} at each of
20. the three locations.
21. NOTE: Your final bore size should be exactly
22. .003, .010, .020, or .030 over standard
23. size. Service replacement pistons are
24. manufactured to precise tolerances to
25. match those sizes.

Source: manual:Magnum_M18_and_M20_Service_Manual.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.