My 2 stroke idles at 1800 to 2000 rpm and revs to 7000 +
Any less and it starts to foul the plugs.
It wont be anything like your vespa
It shouldnt smoke after the rebuild.(unless theres too much oil in your mix) and thats ok
for the first tank.
If the inlet needle isnt seating it will run rich and spit fuel and smoke out the exhaust.