How to adjust the valve of Honda CG 125 motorcycle ejector?

First, open the two maintenance covers on the left side of the crankcase, rotate the magneto rotor counterclockwise with a socket wrench, and the sign of piston top dead center appears from the upper observation hole. At this time, there should be a gap between lifting the two adjusting screws up and down by hand, and then adjusting the valve clearance by hand. The method is to loosen the lock nut and turn the screw, and then tighten the lock nut. What matters is the gap value: most manufacturers' instructions indicate 0.08 mm (8 lines). But this is not the best value, and the best value should be 0.02 mm (2 wires). I have roots here.