What is cc and how it affect the performance of bikes?

cc stands for cubic centimeter. It refers to the displacement of the piston(s). A 100cc engine has twice the displacement as compaired to a 50cc engine. This does not mean the 100cc motorcycle will go twice as fast as the one having the 50cc engine. It will have more power but probably not double that either. There are more determining factors to a bikes performance than the cc's alone. The age and condition of the bike. How much it weighs. Gear ratios, not only of the transmission but if it is chain driven the number of teeth on the front and rear sprocket. Also number of cylinders for the same cc ratings. Compression ratio plays a big part in performance. Then there's the 2 stroke vs. 4 stroke debate. Generally speaking a 2 stroke developes power at higher RPM's or revs than a 4 stroke. Again generally speaking, a 4 stroke has better low rpm power or torque than a 2 stroke.