Engine stalls in neutral

[gregvespa]

I've a 2003 PX200 and once I get it running and ride it for a bit it won't tick over in neutral and stalls.
I've tried turning the screw in the airbox to fix this but that isn't changing anything eitherway.
I'm not very technical but that always did the trick with my other vespas.
Any ideas
Cheers

[ets]

The fact that it shows a fault when it's hot suggests me an electrical problem.

Try a new spark plug.
If it does the trick and it starts again playing up again after about a hundred miles (or more or less) then it is an electrical problem. Possibly the CDI unit or the pick up.

The pick up can also be verified with a tester on the cables coming out the stator to the junction box. Disconnect them all and measure the resistance between cables. The right values should be:

Between red and white (pick up) 100ohm +- 50
between green and white 500ohm +- 50

Unfortunately, to the best of my knowledge, the CDI cannot be tested and you can only try a new/working one.

[Rudi]

if its only happens in idle, and in general you can ride it once you keep the throttle a bit open, means its fuel related.

if upping the idle (turn idle screw clockwise) doesnt help, then there could be two options that i can think of : either mixture is way off tune- thats the screw in the back of the carb, reachable from the outside of the air box
or the idle hole in the carb is clogged

if when it stalls you got no spark, then its probably electrical

[joey]

Of course the CDI can be tested...............
remove the HT lead, lick your finger, touch the HT lead thread and if it hurts like fu*k it's working ok, if it only hurts enough to make you cry a little bit then it's probably not working right! ;
It could be electrical but it sounds more like worn rings.
What mileage has it done?

[dave1967]

Hi
Had exactly the same fault on the way home from Sandford, check the tickover screw on top of Carb is seated properly it may look ok but check it anyway.