Honda BF135A Manual page 400

4) Thoroughly clean the cylinder head to remove any cutting
residue.
5) Check the valve guide bore; it should be straight, round and
centered in the valve guide, insert the valve and check
operation. If the valve does not operate smoothly, the guide
may have been bent during installation. Replace the valve
guide if it is bent or damaged.
6) Check the Valve Stem-to-Valve Guide Clearance (P. 10-24).
10-27