Scooterotica

Any ideas on this one guys? Lambretta, 175 top end, 42mm clubman, 22mm carb. Starts first go from cold but quickly starts choking itself. Take the air hose off, runs sweet as a nut! Put the rubber back on and it dies. Clear airway through hose and air filter box/scoop. Even removed the filter element. Tried three Jetex carbs, one brand new and was running perfect on another scooter. Tried a brand new Scootopia carb, tried and tested on yet another scooter. Think I've tried every jet/slide combination, still no joy. Starting to annoy me now. Never had this problem before. Any help appreciated

Is the restrict or still in the air scoop under the seat? If in doubt, remove the air scoop but keep the air box, just in case it is the air scoop (though this is usually an issue when running at mid to high revs)

try changing the air box for a GP one

Changed the airbox and scoop for a S3 one, not even using a filter element. Airways completely clear

Suddenly happened, slowly got worse, or always been like it ?

air hose weak and collapses under load? Try another air hose.

Chris

Is the choke cable/mech working properly. I'm wondering if the choke is still open a little bit, if the cable is tight or something?

Engine just had a full rebuild. So first time running. Seems to want to cut out as soon as the rubber hose goes near the carb. But will start easy from cold. Runs 30 seconds and bogs down and wwants to die

As Bristolmod says; air hose collapsing. A problem with some Asian imported parts. Try another one that you know works.

The rubber is brand new, but I'll check it anyway. Cheers