A friend of mine has a Lambretta Series I that he thinks may have a tweaked frame. There is some info on the frame specs for the Series III scooters, but not much on the internet about the Series I/II. So I pulled out some of my old manuals, and came up with the crucial measurement. If you have a suspect Lambretta frame, check the distance from the chrome ring to the top of the toolbox. The distance should be 17 inches, +/- 1/8 inch.