WacoNut,

I still have the gages supplied with my old FS-61. The "no-go" gage is 0.01 mm (.00394 in.) and the "go" gage is 0.04 mm (.00157 in.) Therefore, the correct setting is less than .00394 in. and equal to or greater than .00157 in.

OS used to supply the feeler gages with every four stroke engine - before they got stingy.

As a practical consideration, I try to set the valves so that the thinner gage will just pass through the gap. As the valve train wears at all of the contact points with run time, the cold valve clearance will increase. This is most noticeable during the break-in porcess as the wear points in the valve train (cam, cam follower, push rod ends, etc.) I find that a correctly set engine will progress to the point the valves are out of clearance tolerance in the first 1 - 3 hours of running. Reset, and they will tend to remain in tolerance for a long time - maybe a year of normal use. Subsequent adjustments will last much longer as the engine becomes fully broken in.

I believe these same gages are applicable to all OS four strokes, and all Saito four strokes I have had have carried the same 0.01 - 0.04 specification, although Saito to my knowledge has never supplied a set of gages with an engine.