Jetting problem malossi 210

Schaltroller / Classic Motoscooters Vespa Largeframe
1

CARB SETTING:
After seizing several times resulting in broken and burnt through pistons, I would like some advice regarding my carb setting etc. which jets and how many turns on the air screw.
Motor spec: malossi reed valve, 28mm carb, full-circle long stroke crank, malossi 210 cylinder and piston, RZ right hand exhaust.
My main jet has until been 128 and i have turned the air screw 2 rounds. i have been driving with 3% full S oil.
I hope you can help.

Cheers SVEN

2

Dear Sven,
your description does not sound so wrong.
Check your engine on wrong air, means for any leak between bottom of the cylinder and the card. Can be oil seal, carb sealing area, … Also try a larger jet.
It´s difficult to give setting hints by distance but that are the points I would start to look after…