Kohler rebuild kits: get the right one the first time

by Performance Saw Supply

Kohler rebuild kits are our most popular parts, and most Kohler returns we see come down to three things: the wrong bore size, missing that the block was bored oversize, or ring sets that don't match the piston style. Spend five minutes on these checks and the kit fits the first time.

1. Know which Kohler family you have

  • Command and Command Pro twins (CH18–CH26, CH620–CH750, CV and SV models): these come in three bores, 77mm, 80mm and 83mm. The model name does not always tell you which one you have. The spec number on the shroud decal does, and measuring the bore confirms it.
  • Cast-iron twins (KT17, KT19, M18, M20, MV16–MV20): a 3.125 inch standard bore, often rebuilt at .010, .020 or .030 oversize.
  • K-series singles (K90 through K361) and the K482–K662 twins: tune-up parts for the singles do not fit the twins or the KT17 family.

2. Measure the bore

Measure the cylinder about an inch below the top in two directions. If it measures over standard, the engine has been bored and needs oversize pistons and rings of the same size. Oversize pistons usually have the size stamped on the crown.

3. Check the ring style (80mm and 83mm Command engines)

Kohler built 80mm and 83mm Command pistons in two styles. Style A takes a 1.5mm top ring and Style B takes a 1.2mm top ring. If you are buying rings only, measure the top ring or its groove on your piston. A 1.5mm ring will not go into a 1.2mm groove. The 77mm engines don't have this split.

If you are buying a kit with new pistons and rings together, the rings already match the pistons and you can skip this step.

4. Check the wrist pin and rods on cast-iron twins

If you are reusing your connecting rods, measure the wrist pin bore in the small end of the rod and compare it to the pin in the kit before installing.

Still not sure?

Send us your model and spec number and your bore measurement. We will tell you which kit fits.

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