Modern Vespa

silly question.
anyone have a smallframe vespatronic ignition they could look at for me?
is this the right nut suggested for the flywheel on a vespatronic. i think the flange is too wide and the flywheel is a bit rounded down in the hole and i dont think it will sit flush...

This is what I use..

what size is that nut? threads? and what size socket does it take?

http://www.sip-scootershop.com/en/products/nut+flywheel+m12x125mm+serie_78043820

14mm socket. its 15mm tall i assume m12x1.25 as this would be stock crank nut size for smallframe crank right? (mazzuchelli)
the flange is almost the same size as the opening in the center of the flywheel. the nut is 25mm and the inside of the flywheel is 26mm

i was concerned because the edge of the inside of the flywheel hole is rounded up starting from about 2mm from the edge (see pic) and i was worried that it would only tighten down on the outside edge and wouldn't have enough contact with the flywheel. this is likely what happened to the previous owner, this is the same nut he used and ruined 2 flywheels.
i think i need a smaller shouldered nut. maybe 22 or so mm

get a new nut
that one you have looks older and has a wider base than the one I have

does it look like it is stock?
this is what i got w the scooter. could b 40 years old