Why only Vespa? If I were headed to sa with those 3rd world roads I'd pick something with bigger wheels. Not that it cant be done on something with 10-12 inch wheels but it's going to be a rough ride.
The world would be a better place if there were fewer people who felt like they needed to teach other people a lesson.
2007 Daelim S-2 250
2009 Buell Ulysses XB12XT