Modern Vespa

Why does piaggio design a bike so that the fuel line rubs on the underside of the throttle body?

That shouldn't happen. Perhaps there's a cable tie missing in that location?

Piaggio didn't exactly design that bike for off road application, but that still shouldn't happen. are you missing a clip or has it been rerouted in some way?

I only do a little off-roading

rerouted: don't see how it could be. the hose is shaped and has plastic spiral along a lot of it to give it shape.

clips / brackets / zip tie: I ain't removed any and my ex-mechanic should not have needed to touch this.

I do have a friend down the street with an HPE, should be able to stick my head under his seat in the next day or two

You could try applying a piece of braided self closing sheath around the damaged part of the hose to prevent further abrasion.

I'm thinking of something like that ...

that's sound advice and short of replacing the hose what I would do.

and when/if replacing the hose I'd put some kind of sheathing over it or fashion a bracket or some kind of tie to prevent it from further abrasion.

double checked and it's not the throttle body it rests on, but rather the rubber hose between the throttle body and intake manifold.

checked my neighbours bike ... and can see the fuel line also resting there. not just my bike.

Was watching the most recent video by Robot and saw that there's what looks like a metallic sticker covering the part of the fuel hose that rubbed on my scoot