That front seam is the first to go - spreading rust across the belly.
Never understood why Vespa never applied any undercoating to this, or any, areas.
VW used to apply a thick coat in the vulnerable areas - like below the doors....then it is painted over when the body is sprayed. All but invisible afterwards.
https://www.youtube.com/watch?v=sSAZsZhb8rM
Stig
I always thought the older VWs were dipped in a paint bath instead of spray, I seem to remember a short video segment in a VW commercial.
I made the mistake of riding my V-Strom in the winter without the protection of ACF50 and contracted the green cancer of the wire harness, an eekspensive part to replace $1k in parts
The Nissan Frontier I bought last fall, musta came from outside the northeast. 135k not a spot of rust, I had it undercoated, the demise of my Silverado 249k I drove to the scrapyard in perfect running order last month, was a crusty frame that I had already replaced a cross member.