Originally Posted by multipaul
In Germany that "kind of selling" is fraud and forbidden.
What I've written up there, it is too hard! Sorry for that.
Inch, square inch and Kubikzentimeter (=cc) doesn't go together well.
Better suggestion even for people with simple calculators:
Displacement in cc = b x b x s x 12,87
b: Bore in inch
s: Stroke in inch