October 2016 grants British scooterists a rare chance to see one of Innocenti’s factory-built Model C production racers at the Bridlington Trade & Custom Show.
The example shown here is from the Lambretta and Scooter Museum of Vittorio Tessera in Milan. It is one of several factory racers that have survived over 67 years since they were given by the factory to various dealerships and individuals in order to compete in local, national and even international events.
In 1950 Innocenti’s publicity machine went into overdrive promoting the freshly-launched Lambretta C-model. This was their first scooter to feature the sturdy tubular spine chassis for which the brand would eventually become famous. The same technique would end up being the production method of choice for many of today’s scooters.
The Lambretta C was also offered in the LC derivative; which was the first Lambretta with all-enclosed bodywork. Production in the Milanese plant more than doubled to cope with public demand for the C and LC. In turn, a proportion of the profits were ploughed back to produce special competition versions designed to make the Lambretta more appealing and appear sportier.
The best known sport version of the C is undoubtedly the supercharged Lambretta streamliner taken by Romolo Ferri to over 120mph, but there were other more modest derivatives used in road races to demonstrate the reliability of the Lambretta to a receptive public.
With Lambretta only 4 years old, any display of sporting prowess or reliability resonated with buyers trying to make the difficult choice between Lambretta, Vespa or many other emerging rivals of the 1950s.
This is no souped-up street scooter however. Here is the might of Innocenti exploiting every looseness of the rules to produce a scooter that was as close as possible to an enduro bike as they could get away with.
Look at what was changed:
- Frame: Support for long-range motorcycle style fuel tank. This tank does not meet the shortened headstock in order to retain ‘scooter’ status.
- Forks: shortened for a racier riding posture, standard model C suspension design
- Engine: sand-cast experimental engine
- Cylinder: performance with large finned centre-plug head
- Exhaust: hand-made for racing
- Transmission: oversized, strengthened gears for racing
- Carburettor: 27mm Dellorto SS with special air filter
- Brakes: over-sized drums for upgraded performance
Further accessories were added for long distance endurance events. Ernesto Longoni used a model C racer such as this and took the scooter class win in the Liege-Milan-Liege race, covering 2,600km from Belgium to Italy and back in 48 hours and crossing the Alps twice!
While Vittorio’s racer does look similar to a production model C at first glance, technologically the two have very little in common.
Let us start with the engine. This remains a shaft-drive, air-cooled 125 motor that is solidly mounted to the frame. Rear suspension is still provided by a pivoting knuckle section at the rear of the engine, only all the transmission components are re-made in thicker, stronger versions.
The main engine casing itself is a sand cast ‘special’ rather than being pressure die cast like production units.
This manufacturing method is relatively expensive and crude – producing very rough-looking castings – but it is ideal for small production runs and allows changes to be made to the designs quite easily. Innocenti needed to use one-off casings to allow room for the racer’s over-sized transmission, and also to increase the cutaways for the transfer ports.
While the racer looks very odd with its centre-mounted fuel tank the frame is actually based on that of a normal model C, albeit with a few subtle modifications. The headstock and forks are shortened by around 4cm to put more of the rider’s weight on the front and to reduce frontal area.
The forks themselves are based on the Lambretta C design using springs on the front of the fork leg. Longoni used an aftermarket friction damper to improve suspension action for his race to Belgium and back.
Only the very observant amongst you will have noticed that the wheels are also one-offs, with oversized brakes and hubs still fitting inside the standard 4.00-8 tyres. Unlike many of Innocenti’s other racing projects – which were primarily set-up for some of Italy’s top-level bike racers – the model C endurance racers retained the standard scooter’s handlebar gearchange mechanism.
Beyond the long-range fuel tank there were other modifications essential to long distance road races. A quick release spare wheel mounted in place of the pillion saddle will have given the scooters an advantage envied by many motorcycle competitors.
During the 1951 racing season racing C models were used for the Milan-Taranto race, and the mammoth Liege-Milan-Liege hike. Both were won by Ernesto Longoni whose physical and mental stamina allowed him to ride for whole days aboard the Lambretta. His victory in the Milan-Taranto race took him another 1,340 km (832 miles) in 17 hours, 26 minutes. That’s an average speed of 76 kmh (47 mph) on a machine that probably wouldn’t top 60 mph on the flat.
Innocenti’s racing victories became successively more hard fought after 1951, and increasingly irrelevant with respect to their production scooters. According to certain sources Piaggio and MV conspired to tackle Innocenti’s sporting programme with Vespa fighting the endurance races and MV building ‘specials’ for circuit racing.
Innocenti’s answer for the circuit racing scene was the ‘Bitubo’ (twin pipe) racer which had a 4-speed gearbox, aerodynamic bodywork, large wheels and basically had little in common with a scooter apart from the engine directly driving the rear wheel.
This 125cc 4-speed engine also provided the groundwork for the supercharged 121mph Siluro record-breaker, but that’s another story…
Text & photos: Sticky