Modern Vespa

Cheers fellow Vespa-friends! Im installing a new cylinder head on my Leader ET4 150. My old one has it - whatever purpose it has - plugged, my new one does not. Does anyone know whether I need to plug it or shall I just leave it as it is?

Something attaches to that orifice, maybe a breather line? If you have the parts to match to that orifice, then do so, otherwise use the plug-plate from your old unit.

It's for exhaust gas recirculation, an emissions feature. If your scoot doesn't have the plumbing for EGR, you could blank it off.

If a blank plate is unavailable, you could drill and tap the hole for a pipe plug.

Thanks m8s! So blank it of means attach something to plug, and cover it? Unfortunately the plate in my old one doesn't come of. I might just put two bolts in there and some sort of plate. My scoot does not have that emission improving feature.
This is my first post - brilliant to get help like this✨

It's for the SAS - Secondary Air System, that helped emissions go from Euro (some number) to Euro (some number +1). The pipes involved would corrode, and nearly everyone just removed them, sealed them (a hammer works) or otherwise got rid of them.

aha! Thanks. I'll just plugg all the openings and then forget about it. Mine is a 2000, no Euro anything i assume.

SAS delete aircooled Leader

Thank you so much! This really answers my question and helps me fix it🙏👍✨

Not so pretty, but with the tools and time I have available I'm happy with it. Cheers!

Everything started with me trying to replace the sparkplug, in a cold, dark and narrow shed that resulted in ruined threads and a ride down the rabbit hole I'm currently in. Lifting out the whole motor for the first time and so on... Now I am so greateful for you guys and that Robot dude in youtube, he's brilliant!