you can get a kit from ebay in holland, they cost about £12 i think, i got one and it comes with a schematic, and all the gaskets and o rings you need, it also has a new float valve and valve seat, if you go on ebay and search world wide and search lancia beta you should find it.
mine took less than a week to arrive.
also i got lots of spares for these carbs if you need any. i got new accelerator pump diaphrams if you need one.