When new (NOS) carburettors become unavailable, made of that rare material "Unobtanium", then the only course of action is to refurbish the existing carb bodies; vapor blasting and sonic cleaning, followed by the renewal of as many external and internal parts as possible, or indeed what are still available.
This component and perhaps many of those listed below may well end up in your shopping cart:
If you are carrying out engine/gearbox/clutch related maintenance, then why not try this pro-workshop gasket sealant 08C70K0234M?
This component may have other, sometimes unrelated applications within the Honda model range, so please always check by the part-number rather than the description prior to ordering.