Siambretta or Lambretta?

If you have some doubts and you want to know if your scooter is a Siambretta, Siamlambretta o Lambretta; in this article you’ll find the answer!. While they seems quite similars, there are subtle peculiarities which makes them a little different.

General rules

  • In an original Lambretta, both engine and frame were italian made.
  • In the very first Siamlambrettas -due to the incredible in-advance sales demand of the first period-, both the engine and the frame were italian made, but the frame number was national and had the “Siam-Lambretta” badges.
  • In the most modern Siamlambrettas, due to it’s a “transitional” model in the middle of the technological transfer process, engine was italian made but frame was Argentinian made.
  • In an original Siambretta, both frame and engine were Argentian made.

This article will help you to recognize the origin of the frame and engine of your scooter. That information, plus the general rules mentioned in the above, and some knowledge about your vehicle’s story, will help you to find out which is the correct model of your scooter.

As time passed, the lack of good mechanical manpower and the possibility, in most of the cases, of interchange parts from Lambretta to its equivalent Siambretta -and vice versa-, made that some scooters have nowadays parts that not correspond to its original model, making, in this way, this task of recognise the original model more complicated.

Siambretta 125 (estandar/de lujo) vs Lambretta 125 (D/LD) mk1/mk2
Siambretta 150 vs Lambretta 150 LD mk3

Next, we are going to describe the rules that generally follows this three models:


Lambretta’s engine number

Italian engines has a very particular feature: in both sides of it’s number you will find one little stars and the Innocenti logo too.

In addition, there are other signs that proves that the engine is Italian made:

  • In this three models, the cover plate where the sppedo drive is located has the Innocenti logo (if it wasn’t changed).
  • In Lambretta 125 models, the 2-wire external gear selector box is not triangular shaped as the Siambretta one (also known “Addler cheese”, due to it’s shape). Triangular shaped external gear selector box is a 100% Argentinian modification.

These last indications depends on how much “bad maintained” is the scooter. It’s because of that we recommend you to take these advices only if you know how far -relatively- from it’s “factory condition” is the scooter.


In this three models, the original Italian frame number is located in the part of the frame below the fuel tank, behind the carburetor and in front of the back mudguard. In both sides of this number, also, has you’ll find the Innocenti logo and one upside down “Y”. The Siambretta frame number is located below the front seat, in the “U” support in the frame.

  • If the scooter only has the Italian number, it’s 100% Lambretta.
  • If the scooter only has the Siambretta number, it’s probably a Siambretta, although can be also a Siamlambretta, depending on some other factors
  • If the scooter has both numbers, it’s a very early Siamlambretta. It’s because, in the first Siambretta’s period, they had such a high demand that was necessary import Lambrettas and sell them with national frame number and Siambretta badges.
Lambretta’s frame number

Some other indicators of an Italian made frame:

  • The Lambretta 125 fuel tank is lightly bigger tan the Siambretta one; It’s because it doesn’t fit in a Siambretta.
  • The Lambretta 125 D mudguards has the characteristic curve end in the back part and it’s transversal shape is more curved than Siambretta ones. This is why Lambretta mudguards looks like bigger than the Siambretta ones.

Again, the last indications depends too much on the scooter’s story. If you know that your scooter is well conserved with -almost- all its original parts, this advices can be taken in mind.

Considering that the Siambretta Motofurgón (Lambretta FD 125) has the same fabrication base than Lambretta D, we tend to say that all the indications we said in this article (for Siambretta 125/150) applies for the Siambretta Motogurgon, but we don’t have too much evidence to effectively assure it.

Siambretta 175 TV vs Lambretta Series 2 175 TV

This Siambretta model has minimal architectural changes. It’s enough to check if the frame and engine numbers are followed by the little stars and the Innocenti logo in order to know if it’s a Lambretta, Siamlambretta or Lambretta, following the general rules mentioned above.

We don’t have records of any Siamlambretta with two frame number. It’s basically because the Siambretta TV wasn’t as “revolutionary” as the Siambretta 125 was in its moment. We suppose that this gave time to Siam to import and mount the production line more organizedly.

Siambretta 48 vs Lambretta 48

We don’t have records of differences between the Siambretta 48 and its Lambretta cunterpart. We think they were all imported model with replaced badges, because theren’t any record of fabrication line in any Siam factory. If you know any difference between this models, you can tell us and we can publish it in a next version of this article!.

Última actualización: 07/02/2020
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