Kubota — Checking Cylinder Head Distortion

Testing & diagnosis

From a Kubota service manual covering: Hurth HBW 100, Hurth HBW 125, Hurth HBW 150, Hurth HBW 250, Hurth HBW 35, Hurth HBW 50, M-25XPB, M-35B, M-40B. Check it applies to your exact model before use.

Browse Kubota generators & specs →

Procedure

Thoroughly clean the cylinder head surface.
Place a straightedge on the head and measure distortion in six directions A-F.
Measure the clearance with a feeler gauge.
Do not place the straightedge on the combustion chamber.
If measurement exceeds the limit, correct it with a surface grinder.
Be sure to check valve recession after correcting.

Tools required

Straightedge Amazon
Feeler gauge Amazon
Surface grinder Amazon

Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.

Specs & values

Limit: 0.0019 in. (0.05 mm)

Source: Kubota 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.

More Kubota repair guides →