MOPED ARMY

if you dont adjust the carb jetting so it matches the increased displacement of the 70'cc kit, its gonna explode in like a mile.

Other then that, you might wanna get a pipe.

there is no reason / benefit to increase DISPLACEMENT without increasing intake and exhuast.

Think of trying to suck a pea through a straw.

only with metal, that seizes and blows bits of piston into your bottom end.