Thank you for the heads up I did check mine and they are all in good shape I checked them over really good. I do have an extra set just in case.
Z1Enterprises.com sells carb holders. That should be your first priority because if the old ones are cracked you can easily hole a piston running the bike. Next, the carb kits you bought on eBay that come from Japan are sold by a Japanese seller and are not made in Japan.... somewhere else in the 3rd world and not great quality; in fact, poor quality.