the piston must be oversized, because if you still use the std you do not rebore or oversize the piston, it will still eat oil. because the new piston ring is loose in the old bore, so the oil will still eat even if it overhauls and the piston ring is new
you also need to look at the valve guide if it shakes, it may pass even before the steam valve you installed. you also need to look at the valve guide if it shakes, it may pass even before the steam valve you installed. 
@@AutonsTV29 a friend of mine, rebored it to STD with new pistons , so rebuild was not successful. Perhaps spare parts are not authentic here in algeria, what piston rings brand have you used?
if there is no oversized piston or piston ring available in your area, you can buy a new piston and piston ring and then send it to the machineshop, just ask for a liner for the std piston and poston ring.
