RE: NGH 38CC 4 stroke
I think you are mis-reading the saito manaul.
It says that the clearance must be within 0.03 and 0.10mm
"
In that position, adjust with the included gauge and
hexagonal wrench so the tappet gap may be set to
almost zero when the engine is in the compression
"
With a gauge in between the valve and tappet the gap may be set to almost zero.
Not without a feeler gauge....
But you are right that 0.10 is probably too much, as it is at the maximum of the reccomended gap.
I will adjust it to 0.03mm