Make sure it doesn't use hydraulic lifters. If I were to guess, I would say .004-.006. Several posters here say to put both at .004.
Remove sparkplug. Rotate flywheel proper direction. Watch exhaust valve close, intake valve open and close, piston goes to the top of the stroke. I use a small screwdriver and gently feel when the piston gets to the top of the stroke. With piston at the top of the stroke, set both valve clearances.
Use same procedure for other pistons.