I have heard of '10mm' saws for some time, and realize that I didn't really understand what that meant - it sure isn't the diameter of the piston!
Judging from your photo, it is just the spacing at the top of the connecting rod? Are the pistons and cylinders pretty much the same otherwise?
Seeing as I have already exposed and acknowledged my ignorance; could the piston / connecting rod in the photo above be shimmed to fit with spacers?
Thanks.
Philbert