Modern Vespa

Hey everybody, I am having a very annoying problem with my LX50 (2006). When I pull up to a stop the vespa starts to stall if I do not give it throttle (have to apply break and throttle at same time while at stop). If it does stall out then turning it on immediately afterwards is next to impossible. I have to hold down ignition for a good 15 seconds while it slowly comes back to life, even after it might light up but will refuse to move (check video link attached). I have cleaned the carb, put new fuel in it and put new valves in. Does anybody know what could be going on? The problem is so bad I haven't been able to drive it safely.

https://vimeo.com/user103988320/review/366374730/55f822d7ab

What do you mean by putting new valves in?

I used to have a similar problem with my 2006 LX 150. The problem was solved by a valve adjustment. I was going to suggest the same to you, but you mentioned valves.

I'm just confused because to my knowledge all Vespas have adjustable valves with nothing to put in (not bucket and shim, etc).

Meant to put hoses not valves!! Total brain fart. Which vavles/how did you go about adjusting them?

How many miles are on the bike? Do you know if the valves were ever adjusted before? Is it a four stroke (4T) model?

Assuming 4T, then the valve adjustment procedure should be something like this: https://modernvespa.com/forum/article26722