0.18 to 0.22 mm
0.0071 to 0.0087 in.
This took less than 2 minutes to find on Google, try Kubota D1503 valve clearance.
I was going to say .007"-.008" off the top of my head but double checked to be sure.
Brian
And btw, "running the rack" refers to setting the fuel rack on a Detroit, not adjusting valve clearance.