This is the RaceTour cylinder kit. They are available with 195cc (Ø=65mm) for the small casings (125 - 175 cc) as well as with 225cc (Ø=70mm) for the 200 cc casings.
Both offer significant improvements with respect to power.
This kit is for fast road use. The engines are easy to ride and feel like an original Innocenti Lambretta engine with double the power of a standard 200 cc engine. The kit is easy to fit and comes with all the needed studs, washers, gaskets and so on.
Update: Piston made in Italy by Meteor with running-in coating.

Features:
Ceramic plated alloy barrel
Four fixings of exhaust stub
200 cc inlet stud spacing on small and large block barrels
Italian made (Meteor) piston kit with running-in coating (195cc =Ø65mm, 225cc =Ø70mm)
Two 1 mm piston rings (made in Italy)
Fully CNC machined anti warp head made from billet alloy with recess into bore and four additional fixing screws (8 fixings in total). Made in Germany.
Compression ratio for highest reliability
Porting spec for high powered touring with lots of torque and wide power band
Improved fuel economy saves money paying for the kit long term
Improved casting thickness around the cylinder head and base gasket, so it can be easily tuned
BGM CYLINDER KIT FITTING GUIDE