Lambretta Li125 Series 4 / Lambretta 125 Normale.

It was long believed that the Series 4 was a special or government order, but that theory can now be dismissed. No public information, sales brochures, or user manuals were ever produced, leaving only speculation for many years. Pete, a leading authority on these machines, has spent years trying to answer questions regarding the mysterious Series 4. He has written several articles and a dedicated chapter on the subject in his book The Lambretta Bible.
As a long-time enthusiast of all things Lambretta and a member of the BLA, I have gathered numerous documents over the years. After a conversation with Pete over coffee at my house, he set me one of his usual challenges — to uncover everything I could about these machines.
Touché, sir — I see your challenge and raise you, my friend. I sent him a text with a few references to files in my archive. He was soon writing what may be the final article on them, since published in Classic Scooterist Scene magazine.
In addition to that article, I’d like to share some technical information that may help paint a clearer picture.

We can begin by examining production of the Li range — a glimpse into life on the Innocenti factory floor. To me, this is vital to understanding Innocenti’s intentions and market positioning.

Li125 S3 December 1961 – June 1966
Li125 Special October 1965 – January 1969
Li150 S3 January 1962
Li150 Special September 1963 – October 1966 – This was then replaced by the 150 Special X.

Innocenti ended production of the Li125 Series 3 in June 1966, while its larger-capacity sister model, the Li150, remained in production until January 1967. After a three-month gap in production, the final 274 Li150s were built for the American market. We know this from the factory’s end-of-year production sheet for 1969 “Chiusura a consuntivo produzione anno 1969.”

The earliest records we have are the Homologation Certificates from the Italian Ministry of Transport. The updated certificate of conformity, IGM 0902 OM — replacing that of the Li125 Series 3 — is dated 01/08/1968 to introduce the Series 4 to the market, and shows Innocenti intended, if only for a short period, to continue production and offer a basic Li125 model.
The Li125 Series 3 also had several amendments to its homologation papers that mention the Series 4, conforming to these updates.

2297/2250/4 – 13/04/1962
0225/2250/4 – 06/07/1963
2803/2250/4 – 06/09/1967

Taking a look back at the end-of-year production sheets, 1,472 Li125 Normale were produced in September, October and November of 1967; however, the frame prefix changed to Li4 and frame and engine numbers started from 148000, as noted on the homologation certificate.

These 1472 machines, featured various inconsistencies which for years, Pete has noted the different characteristics of the components on surviving examples, from studying various factory amendments issued by Innocenti I have compiled the following part numbers for all of the updates issued to the Li 125 Normale. Production of machines on the factory floor, saw all old stock of parts used until depleation and subsequently replaced by the following updated components. These parts were intended replacemnet parts for the Li125 series 3 too.

Pre Mod – Post Mod
19111015 – 19411015 Cylinder Head
19111003 – 19811005 Gasket
19030003 – 19430008 1st Gear
19830009 – 19430009 2nd Gear
19830005 – 19430011 3rd Gear
19830001 – 19530501 Main Shaft
00412348 – 00412435 Main Jet of 98
19911004 – 19411004 Manifold
19955081 – 20130103 & 20130104 L & R Springs
19955083 & 19955082 – 20130105 Plate Spring Retainer
19955150 – 19955098 Right Hand Side Panel
19955140 – 19955097 Left Hand Side Panel
19950086 – 19950117 Horn Casting
19950069 – 19550508 Badge Retainer
19022015 – 20070004 Protection
***NEW** - 20034023 Cup-Badge Pin
19250071 – 19550509 Badge
***NEW** - 20020046 Ball for Fig:89-90
19960027 – 19560026 Bush
19060090 – 19560100 Piston
15060070 – 20320048 Buffer
19960010 – 19560030 Fork
19960060 – 19560120 Lever
19960050 – 19560110 Lever
19986017 – 19586505 Tie Rod
19086018 – 19586504 Gasket
19986010 – 19586501 Luggage Box
15086017 – 19586021 Tie Rod
19910020 – 19510510 Cover with Fig:28-29
19930031 – 19530502 Shaft
19950021 – 19550024 & 19550025 Buffer
19945110 – 19545140 Rear Hub With Cone
19045003 – 19545006 Cone
15044110 – 15044110 (post mod) 19544120 (pre mod) Nut.
19023008 – 82128011 Nut
19916018 – 22016260 Inlet Manifold
19950053 – 22050053 Right Hand Footboard
19950054 – 22050054 Left Hand Footboard

From this, it’s clear that the anomalies found on surviving examples result from a mix of pre- and post-modification components. As such, these post-modification parts were subsequently made available to Innocenti spares stockists globally. Series 3 parts catalogues should have been updated with the above part numbers. Series 4 machines were issued with an Li125 Series 3 user manual when purchased.

Are they rare, and do they command higher prices? In terms of rarity, yes and no — they are, after all, an evolution of the Li Series 3 — but they remain highly desirable among Lambretta enthusiasts. I don’t believe that warrants a significantly higher value, although for insurance purposes it’s worth noting that these machines are hard to replace and appear for sale only occasionally.

Pete and I continue to grow the Series 4 register of surviving examples by adding more frame and engine numbers as they come to light, and noting any pre- and post-modification parts fitted. Survivors have been found across Italy, and many now reside in the UK. The global total of recorded survivors now exceeds fifty examples — currently standing at 64 as of December 2025.

We’re keen to find as many owners of the Series 4 as possible. If you own a Series 4 Li, please contact us so we can add you to our database and better understand how many of these rare Lambrettas still exist.

Johnny