post detailed pics of carb venturi.. the hole through which air flows into engine,,,measure it,, if its diameter is 13mm its of 50cc bike,, if 16mm its of 70cc if 19mm its of 100cc if 22mm its of 110cc,,,
and remember if the di is small u will get excellant low end power and very low top speed,, if its huge dia then u will be getting low power in low end but high power in full end and greater top speed,, only for straight areas better,small dia carb is good for hilly areas,,
exhause,, show pics however replacing it will have negligible affect,,,
sprockets,,u can play with it,, and can adjust it according to ur mari,, u can make it give good top speed but pic will be greatly compromised,,,or make it increase pick but reduce top speed,,and enjoy it on high slopes in mountanious area,,
without serious engine mods u wont hve any significant gains,, all that u will be getting is a compromisew between top speed or pick,
i would suggest u stay stock,,
