Vespa PK 50 S kit?

I have a vespa pk 50 s with a tuned exhaust and a dellorto 16/16 carb, i was wondering what kit would make my bike hit 40-45mph, and weather their are any other parts which could do this.

 

 

Thank you

 

James

sorry and a 19/19 carb

a pollini kit to what size you want will do the trick [:D]