I dunno much about carbs (my first car was a fuel injection, a 1982 Golf GTI), but I love reading about them.
You two boys might enjoy this particular subreddit: http://www.reddit.com/r/EngineeringPorn/
There is a weird vintage injection system for Lambrettas and of course the new Vespas have it for emissions.
Fuel injection is certainly far more economical and continues to provide the right amount of air and fuel even when things like temperature or fuel quality change. On a big bike a can see how that would work well, I've been through the pain of trying to balance a 4 carb setup on my old Suzuki GS50, not a good afternoon.
But on a tuned 2 stroke traditional carbs work well (more so with a read valve), you don't get anything like an even spread of power you get a power band in a specific rev range. This is mainly driven by the cylinder porting buy mostly the expansion chamber exhaust, it a bit like an old tuned car 'coming on cam' .
It's not a setup that gives good fuel economy, a great deal tends to get spat back on an open mouth carb and because of the tendency to ride them hard to keep in that power band even more fuel is used, I don't have it for tansport.
That said in a low state of standard tune Vespas specifically are very economical, reliable and extremely boring !
It's fairly common for people to get 25BHP from a tuned Lambretta engine, it may not sound like much but it would be enough to put the fear of god into most. Fitting a Yam 350 YPVS has become a popular mod and one I intent to attempt one day. The best ones use an airshifter for the gears and hide the radiator inside the legshield toolbox, you can get the panels on and they can look pretty standard...but do up to 120 MPH....
