Motorcycle Repair: how many ccs did i gain by milling down my head, piston displacement, compression check

Question
i have a 90cc E-ton vipor I did a compression check before i milled the head and got a reading of 120. after i milled the head i got a reading of 210. can you tel me if i gained cc's or horse power. and how much
                     mstfields@yahoo.com

Answer
Hi George,

Milling the head changed compression ratio. Piston displacement and stroke is unaffected.

With compression that high, it may be necessary to run race fuel for the engine run to properly.

You'll have to determine what's become of the engine performance wise. It's probably a mean machine!!

Respectfully,
Mark Shively