Saito recommends .1mm (.00394") to .04mm (.00157") valve lash.

The feeler gage Saito sends is actually .1mm & is a maximum gap.

I think they use .04mm as a minimum because it would be impractical to use anything less in a feeler gage.

The aluminum cylinder WILL expand more than the steel valve train even IF they were @ equal temperatures which they are not when the engine is running. The cylinder /head assembly will be much hotter than the pushrods/valve train when the engine is running.

ANY clearance when cold will increase as the engine gets to operating temperature.

Case in point: The old Harley Davidson big twin had a (solid lifter) valve adjustment procedure when cold of taking up the lash until the pushrods could just be spun W/slight drag W/the fingers. In other words, as near to .0000" lash as possible. The cylinders, even though they were iron, were greater in mass than the (sometimes aluminum) pushrods/valve train & would run warmer when operating thus the lash would increase as the engine reached operating temperature. The greater mass will expand more than the lesser mass @ simlilar temperatures even when made of the same material.

In the case of Saito engines, not only is the cylinder/head greater in mass, it is made of a material than has a larger expansion factor than the valve train.

Theoretically, the engine will run just fine W/.0000" lash cold as long as the valves are not held off the seats. As the engine warms to operating temperature, valve lash will increase.

Setting the lash @ the recommended minimum of .00157" (.0015 is close enough) will result in more power & less cam lobe/tappet wear.

I set valve lash on my Saito engines W/slight but noticable drag on the .0015" feeler gage AFTER THE ADJUSMENT IS LOCKED DOWN. I check for a slight "wiggle" in the rockers to assure that there is some (minimal) valve lash.