I know of two options you can go with and i can sell you what you need to do either set up.
1st wheel adapters that take the rear bolt pattern down to the standard honda sport pattern and buy any 10" rear rim you want
2nd rear hubs that have the bolt pattern already and same deal with the rims
the wheel adapters will make the quad alittle wider and much more stable total width will be about 54" with the adapters and with the hubs the quad will be about 52" wide
contact me at 513-752-0088 if your interested i can get you the rims and tires also my name is Shayne just ask for me if you you call