Modern Vespa

vespa px 125 with electric starter and muffler with catalytic converter), when the engine is on, but you are standing still, it is impossible to shift from first speed to neutral. As soon as you turn off the engine - you shift without problems. How to solve this problem? thanks in advance to everyone

It's probably that your clutch is dragging, not fully disengaged. Best case you can adjust cable for more disengagement OR you may have warped steels and are due for a clutch rebuild.

Thanks for the answer. We checked the clutch cable earlier, the clutch too - everything is good, the selector is new, just magic(

If you believe that your clutch is good, try tightening up your clutch cable until your kickstart just starts to slip then back off just a little bit. That should let you fully disengage the clutch which seems not to be happening here. Did it used to shift to neutral OK when running? Your clutch cable stretches over time.

while moving it switched normally. but I will follow your advice and do a test, thanks for the help

Did you try downshifting to neutral before you come to a complete halt?

Always put it into 1st before stopping at lights & hold clutch in till lights change.

If you have driven a Mini without synchro in 1st you will understand.