for a stock puch engine on a free spirit
Dellorto 15.15 Cable Choke Carburetor
http://www.1977mopeds.com/catalog/index.php?main_page=product_info&cPath=22_73&products_id=465
or
Dellorto 15.15 Lever Choke Carburetor
http://www.1977mopeds.com/catalog/index.php?main_page=product_info&cPath=22_73&products_id=467
i'm assuming the lever choke but i'm not sure!
this and a proma gp muffler should raise me up from 25mph, no?