I get all my carb bits from nrp-carbs check them on the net. The web site has never been finished but if you send them an email they get back to you in about 48 hours.
For my 2MA they have supplied float valve seats with float needle, float bowl gaskets at an affordable price.
They did quote me for genuine mikuni atomiser(emulsion tubes) and needles but these not cheap.
The jets and float do not seem to suffer from wear as they are not moving parts.