Scooterotica

I know they have different engines but I've read in a few places that Innocenti just bored out the 175 to 200 and sold them as 200's for the UK. I'm unsure if this is really true

This topic pops up every couple of years or so. In my 25 years of dealing with these bikes I have never seen (in real life or online) a confirmed over bored TV175 to 200. That's not to say there wasn't some experimental top ends floating around in 1964 but so far nothing has surfaced. If you bore out a 175 cylinder to 66mm it becomes very thin very fast around the cylinder studs and fins.

Yes agreed this rears it's head every couple of years. Enthusiasts did find bigger pistons and bore cylinders to fit and there were pistons available to take capacity to nigh on 200 ccs. So yes it was done but whether or not by Innocenti or Lambretta Concessionaires is not factually recorded. There was a readily available 200 piston but it was 65 mm and not 66mm. I have bought it and done it with good result.
The other way (after the introduction of the 200) was to fit a 150 crank and a 66mm piston and again I have done that with success also.
For information tuning specialists were offering 150 - 200 conversions as well as 175 - 200 conversions.
Only 2 years ago I sold a TV barrel bored to 66.2mm and it's still in use so it's all possible.