engine machining question

[AMCQ46]

the old piston had suffered a lot of little siezures, and took a lot of fileing to take the metal pick up off.............but your right, I bet it only gets 1mph extra!........but I am hoping it gives it back a bit of the missing midrange............but perhaps getting off any of my other bikes onto a 20yr old 125 I have no realty of what midrange is

[edds11]

I think my friend you would be quite suprised, look at the % increase in cc's