The entire Li range uses the same design gearbox but there are quite a few different gearboxes available. It is quite common to find loose gears and it can be hard to know what gearbox it is from. This section should help you make sure that you either have the right gearbox in your Lambretta or even identify that odd gear you found.
Also you are able to check when you have a valid combination that works OK, especially when you are buying a scooter in parts this can be very help full.
The gearbox exist out different section; the cluster, the 4 gears itself and the sliding dog with main shaft. Check the gears page for details.
So you have your big box of loose gears and now all you have to do is identify each single gear. This table will start you in the right direction. Use it in conjunction with the individual gear identification to positively id any gears that are not obvious.
TV/GT 200 4th
SX200, TV175 series 2 & 3 4th
Li150, Li150 special 4th
Li125 series 1,2 and early series 3 4th, SX150, GP150 4th
Li125 special, GP125, GP200 4th or TV/GT200 3rd
Li150, series 2 Li150 rallymaster (diam. 96.2, 5teeth=34.6)
SX200 and TV175 (diam. 95.6-95.9, 5teeth=34.2)
Li125 series 1,2 and early series 3, SX150, GP125/150/200 3rd or TV/GT200 2nd
SX200, TV175 series 2 and 3 2nd
Li150 or Li 150 special 2nd
Li125 series 1,2 and early series 3, SX150, GP125/150/200, rallymaster 2nd