Measuring for rebore

Paid $100 au to get a postie bike overbored and as I walked out of the shop I lifted the bore to the sun and could see tool marks in the finished job. Went home and measured it hoping the guy had left it a bit small.
Dead on size. Damm.
The barrell and piston were rare 125cc ones that I will probably never find again so I had to wear the ballsup.
Later I honed it to take the marks out because it was blowing smoke , so now it won't last as long.
Should have done the job myself.

I must correct my original post - I was not given correct information. There are a few engines where the PISTON is measured part way up from the bottom - the taper thus making the bottom of the skirt extra snug. This was confirmed by a former Husky dealer mechanic from the '80s but he told me Huskies are measured at the bottom.

Once again sorry for the mis-information.

Measuring your piston at several points, from the bottom of the skirt then towards the wrist pin, will reveal to you the largest diameter of this particular piston. Set your clearance from that diameter. Different pistons may have the largest diameter at different points from the bottom. I'm certain this is the measurement you desire.

Always measure up and down on the piston (Exh side to Int side) the correct measurement is the largest measurement.
Usually can be from 1/4" to 1 1/2" or higher up on the skirt of the piston depending on the size of the piston.
Remember pistons are not round, it's important to measure front to back , take several readings up and down on the piston, the largest dimension is the go to dimension.
Bore to this dimension and hone for your clearance.
Different pistons have different clearances a true forged piston will be different than a cast piston.
Example forged would want .004 and a cast .0025.
Later George