Getting hold of brand new carbs for older classic machines is almost impossible unless you are very lucky to drop on NOS items.
All is not lost though; most of the essential internal jets, diaphragm, floats, seals and external screws are still available. Vapor blasting the crab body, sonic cleaning of the internal parts and renewing as many parts as possible will bring the carbs back to fully functional condition along with cosmetic improvements.
Other components listed below you may wish to consider:
If you are planning any engine work then try this pro-workshop gasket sealant 08CRAHLG120G. It is very easy to apply and with excellent results.
Add as many items as you wish to the same shopping cart, new O-ring seals 36024512005Y11453600 float chamber gaskets 5Y11438400 & needle valve set 1JK1410701 for example, and still only pay the same single fixed price shipping cost.
This component may have other applications within the Yamaha model range, so please make sure you order the correct part number for your application.