Pretty much any of the various carbs that were used on the 750 engine will work. GPz bikes used Minuni BS34 carbs, and the ZR-7 bikes used CKV Keihin's. Unfortunately, carbs are not cheap these days. And don't even think about trying to buy a used set and throwing them on without performing a complete rebuild. Contrary to popular thought, installing "carb kits" is tomfoolary and often causes more problems than it solves.
Do you not have any carbs? What's the problem?
BTW, I've got a nice set of stock Keihin 34's that I'm about to rebuild for resale.
