Piston information 400cc

Hi I'm wondering if any of you kind gents could help me with the measurement from the face of the cylinder to the top of the piston. I got what I thought were new pistons but they are nearly 3/8 of an inch higher than the original ones. I also have some Honda pistons which I'm looking at fitting. If anyone could help me with the distance that would be greatly appreciated. Thanks in advance Chris.

Hi Chris

When I was looking at the compression ratio on my machine I measured the piston crown as being 5.85 mm lower than the cylinder top when the piston was at TDC.

My engine has Imp pistons fitted, which have a gudgeon pin centre line to crown height of 26mm whereas the original ABC piston is 21 mm. Therefore, based on this the ABC piston should sit around 10.85mm from the top of the cylinder when at TDC. hope this will help?

Thank you for you quick response I will measure and see what mine are. Many thanks Chris