Check with Jon - if you ordered the whole kit (intake, cables, etc) I can’t imagine how it would be failing like that. He takes great pride in that solid intake manufacturing and design and should be able to troubleshoot it over the phone or emails for you.
I just installed a Delorto 24mm kit from Casa Lambretta to replace an old Jetex that I had, but with the new carb on, the fuel flows and fills the bowl, but nothing is drawn through the carb, and even placing my hand over the carb mouth leaves it bone dry. No other changes were made and it ran fine before. I’m at a loss.