Modern Vespa

usually i only do 91, as thats what the dealership recommended...but i came across a gas station that was all out of everything else (87 89 91) and only have 94... so i was just curious if its bad to put that high a number in your scoot? thank you

Higher is always good.

Been using 95 in my Vespas for years.

Australian 95 is the same as American 91
American 94 is the same as Australian 98

both are good, I normally use australian 98

ref: http://www.pencilgeek.org/2009/05/octane-rating-conversions.html

not necessarily. higher octane resists pre-detonation better but it also burns hotter. understandably you can squeeze it more before it wants to go kablooey, and you get more bang out of that, but you have other variables at play such as ignition timing, cam phasing, inlet timing and exhaust scavenging that may make that all a moot point.

running a little more isn't going to hurt it, but you're not going to see any real, tangible gains-- at least not on these motors. .running less, you're more than likely to see a minor detriment in performance.