@syedmoazzam! @vickytulla! Does that wikipedia article also tells you which fuel to use in those low compression engines? Because what i have read that you can't just tell on the basis of "engine compression" ALONE. And other things like Engine Type, Design, Size and Horsepower also matters. Whatever article you will find on the web, will mention compression of a car, not of a bike. If the latter, then it doesn't mention what kind of bike, whether high performance or commuter.
I remember that i searched on this high enough but only remembered the final verdict (as it was a long time ago), which was that ALL commuter bikes in Pakistan should use Regular petrol, and NOT Hi-Octane, and using Hi-Octane will increase their wear & tear, despite the obvious increase in performance.
Anyway, as Piaggio's owner mentions 89 rating, i think its okay to mix both regular and hi-octane fuels. But then again, the cost increase vs. performance gain is significant, with Hi-Octane being much expensive. So i for one will not opt for it, unless i got deep pockets.