Hello, I am measuring the diameter of 82MM YCP piston to do the piston to wall clearance.

Why my set of piston middle measure point diameter 0.03mm larger than the skirt? As my knowledge, the skirt of piston is the biggest point in the normal.
My measurement:
Piston middle : 81.99mm
Piston Skirt: 81.96mm

Is it normal? And which measurement I should use for do the clearance?
May I do 0.05mm clearance for piston skirt? If not , how many clearance for my set piston should be fine?

 

You will need to contact the manufacturer to see where you do the measurement. It may not be the same spot as OEM pistons.