Ok, first and most important bit.
Stating everything is perfect is wrong and not helpful.
First thing that springs to mind is the reeds, if they are not sealing properly you will have issues.
Also the exhaust, is that clear, a 2stroke pulls air back from the exhaust during the cycle, if that is badly restricted or blocked by a build up of crap (on my daughters bike the 20mm pipe on the exhaust was so choked a pencil wouldn't fit) it will reduce the draw.