is this what you are looking for?

http://www.jbdistributingextrememini...x717tofrc.html

http://www.jbdistributingextrememinis.com/49pepa3.html

those are performance parts with sprockets on them, do a google search for pocket bike parts you will be amazed...

I dont know much about mini-bikes but i guess they do have different size sprockets, i figured they were all the same...