Scooterotica

I recently bought a new air filter and carb kit for my Li 150 ser. 2. The scoot runs great with the filter hooked up but as soon as I clip it in place fully it kills the scooter.
Any ideas?
I ran this scooter for years with the old filter and bellow hooked up but the bellow was rotted and didn't seal against the filter, so I decided to hook it up properly and this is what I get?!
Cheers

sounds like its been running with a "leak" for years.

Over time, has someone altered the jetting to make it work? I would check jets etc first and revert back to what they should be if thats the cause

Chris