Two cyllinder Lammy on it's way...

[Progetto 300]

PROJECT 137 BIS

The twin-cylinder Lambretta has been revived in Paullo after Innocenti stopped its production 40 years ago for market related reasons. It will be called TARGA TWIN 250 to honor the mythical Sicilian car race Targa Florio, started a hundred years ago.

We hope this name will bring some luck to the project.

Many projects and experiments came from the Innocenti business, a company that without doubt could be described as the most up to date, well organized, and largest industrialised commercial structure in the world in the field of two and three-wheelers from 1941 to 1971.

Whilst many of the Innocenti projects remained on paper only, many others were developed as prototypes but then subsequently abandoned for economic or commercial reasons, although the development process provided useful experience for the company from Milan.

Together with the drive gear shift model, the twin-cylinder four strokes competition model, and the single-cylinder fuel injection model (to name but a few), Innocenti released the twin-cylinder two strokes model (Project 137). At the time this was considered an evolution of the SX 200, a model at the top of its range.

From 1957 Innocenti left the management of racing models directly to head office and to the Lambretta agents (see the records, endurance and speed races), but they were always keen to produce models perceived to be sporty, but also within everybody's reach.

To be able to compete with the first readily available sporty scooter which appeared on the market (the Vespa GS), the Innocenti company introduced the TV (Turismo Veloce) line, with the 175 TV first, second and third series, followed by the SX 200.

Innocenti wanted to offer something unique and interesting to that part of the market and most of all to those clients across the Channel where twin-cylinder scooters were already known. In 1966 Ferdinando Innocenti asked the Centro Studi (development centre) to come up with something really innovative to improve performance while maintaining the single-cylinder style, which was at the top of its range at that time. Within just a few months a twin-cylinder 50x50 200cc project was taking shape. The engineers and designers were also continuing to studying all of the suggestions and designs that had been received. The objectives were to have a powerful and strong engine especially good in acceleration, with an aristocratic look, safe braking, excellent road holding, 4 or 5 speed gearbox, and the possibility to adopt rims with 12" tires.

With all these features, the competitor Piaggio, should they have chosen to follow suit with a twin-cylinder design, would have been destined to run into trouble. In fact, the creation of a twin-cylinder Vespa with a lateral engine was unthinkable! The engine would have had to of been positioned in a different custom designed frame with a more modern line monocoque body, but this was never realized.

A year after Mr. Innocenti's request, the Centro Studi had completed the project. The final drawings and modifications were dated April 1967.

In the middle of July 1967 the new engine, mounted on an SX 200 frame (apparently unmodified) was ready.

Luigi Innocenti called Mr. Cereda (who had been for many years the test driver at the Lambrate household) to his study. Being received by the "big boss" was always a great honour.

It was a cloudy day and he had absolutely no idea of the reason he had been called to the meeting. Luigi Innocenti sat at the desk with the head of the technical office, the engineer Pierluigi Torre. He said to Cereda: "If tomorrow it does not rain, you will have to ride the Lambretta to Rimini and back." And after a pause, using a lower tone of voice, he added: "You will ride it to the limit, and if you are unable to break it you will have to look for a new job".

The departure was postponed for few days because a rev counter was added and the carburation re-adjusted. The mechanical rev counter was attached directly to the pinion through the chain case side. Cereda, with his helmet, goggles and his white overalls, and a small fuel tank attached with a rubber on the back of the saddle, got on the motorcycle marked # 137 at 10 am and took the newly built highway towards Rimini as asked.

No one knows what went through his head while taking that long ride, stopping only three times for fuel. For sure, he couldn't avoid thinking about Mr. Innocenti's last words.

At 3.15 pm he returned, having ridden for more than 400 km at speeds that presumably reached 125 km/h, and without having had a single problem.

After a sleepless night, Cereda sat at the meeting, bright and early in the morning, worried that he had indeed returned with the prototype "twin-cylinder" working perfectly. "The boss" already knew that. He was happy that everything worked well, and was quick to reassure Cereda that the dismissal threat was only a joke.

Finally the twin cylinder was presented to the press, and more importantly to the English importer Mr Agg, at the Monza racing circuit not far from Milan. Mr. Agg, who was at the event with his guests, was enthusiastic, but not as excited as the lady beside him, who reportedly jumped for joy every time the twin-cylinder passed in front of the stand.

During the presentation it was discussed how many scooters the English market would be able to absorb. Figures from three thousand to ten thousand were cited.

However, what had seemed to be a way to secure the future success of the motorcycle from Lambrate was, in the end, destined to go no further than the production of only two prototype models, both very similar to each other. One of these, the one with aluminium cylinders, I had the pleasure to ride ten years ago.

We can say that these extraordinary twin-cylinder scooters did not receive their deserved success because they were created in the wrong period of time.

The SX 200 cost 190.000 liras at that time and it was predicted that the cost of the new twin-cylinder would be around 230 to 240.000 liras (three months pay for even a specialised worker). For comparison, the Fiat 500 in 1968 cost 475.000 liras, but offered extra comfort, protection and stability, and probably took away sales from the scooter. At such a cost, the commercial future of the bike was not so bright. In fact, production didn't work out, and the only two models built were abandoned for years in a narrow storeroom at the factory.

Today the factory prototype model with aluminum cylinders can be seen at the Lambretta and Scooter Museum in Rodano, while the whereabouts of the second model are unknown. Perhaps it has been brought across the channel forever?

Many Lambretta owners dream of owning a twin-cylinder Lambretta. There have been many well known examples of twin-cylinder engines obtained through welding. Some have been used with discrete success in side-car races on English tracks, while some others were prepared by clever, mechanically-minded enthusiasts. They remained unique pieces of work, but were never able to guarantee the same level of reliability and power as the single-cylinder.

An engine like the "Project 137" has never been created before. It is the combination of custom-made parts originating from more than 22m² of drawings.

The idea to build a twin-cylinder TARGA TWIN (project 137 bis) came from collaboration with Mr. Franco Dell'Acqua, and our common desire to enjoy the thrills of riding on a bike with an engine like that. Absolute interchangeability, ability to use an air-filter, original silencer, electronic ignition, and the original bodywork line were all prerequisites for the building of a modern day Lambretta twin-cylinder engine. Performance would be increased by using a higher displacement: 250cc (54x54 increasable to 280cc) against the original 200cc (50x50), electronic ignition Varitwin (Varitronic), two carburettors by Dell'Orto with diameters from either 26-28-30, and Nicasil cylinders with 4 well drawn transfers.

All these modification plus the lightening of the clutch group would allow 35cv and reach 160 km/h.

The use of a cowlings for the cylinder and fan made of carbon fiber, titanium bolts and screws and other details made of ergal high tensile alloy would give the engine unit a more sophisticated and sporting look. The equipment and manufacturing processes used to prepare the 137 bis have all been set up in a way that it is possible to produce a high number of machines.

Only a few details are identical to the original twin-cylinder such as: the silent block, 4 or 5 gears, 4-5-6 clutch plates, all with modified disk, modified case lid, modified silencer, modified rear hub. Some of these parts could even be used on all the other Lambretta models.

With regards to performance, the Targa Twin will not fail to meet expectations of owners: whilst being powerful, the unit is not designed to be super-powerful, but flexible with no vibration, with plenty of torque will be able to transform a Lambretta into a fast racing bike able to pass any Japanese scooter even if higher powered.

Although the Targa Twin has been designed as close to the original, economics and advances in technology sees the 137 bis use its own innovative parts, which compared to the original prototype are as follows:

1. Cylinders are fixed to the base with 4+4 screws and not with cylinder studs; cylinder heads are fixed with 6 bolts at the upper part of the cylinder. This solution has been adopted to allow dilatations avoiding tensions or distortions of the thermal group.

2. Electronic timing adjuster ignition (Varitwin) is derived from the tested Varitronic ensuring the Targa Twin starts easily, and also gains an increase in power. The Varitwin even improves fuel economy and efficency making the engine able to meet many current legislations regarding pollution levels.

3. 4 transfer cylinders with 2 rings per pistons or for racing or other applications 5 transfer cylinders with 1 a ring piston. Modern design and great performance especially with the exhaust and possibility to raise power and displacement.

4. 4, 5 or 6 disk clutch depending by the usage. Aluminum clutch disks are currently under test.

5. The crank shaft although is derived from the original project, has been improved to ensure it not only works, but is reliable. The connecting rods, pistons and bearings are all of excellent quality.

6. Exclusive right is the mechanical labyrinth seal between the two chambers. Coming from the aviation school and foreseen in the same way by Project 137, it'll give to the Targa Twin a more refined technology.

7. Case, cylinders and heads are melted in sand (more precisely in ashlan) by gravity, with a temper and austempering treatment as done on the 137 twin-cylinder: the engine experts will appreciate. Even if expensive, we couldn't do it differently since we had to follow certain technical rules reserved to exclusive engines of high temperament such as racing engines.

The used process allowed to make all the updates and improvements every time was necessary during production.

We remind to all pressure die-casting lovers that it's like to make a comparison between orange-juice and Chianti; the case obtained adopting this metallurgic process is slightly heavier but more robust and safe thanks to the foundry model.

Of course there are customers who always wish to push performance higher and further, in the UK people who wish to push the power of the Targa can count on Mr. Charlie Edmond of Performance Tuning who will take care of the racing point of view of the engine with an appropriate silencer and tuning.

After 40 years from Mr. Ferdinando Innocenti idea and 100 years after the first Targa Florio race, a Targa Twin prototype has been presented with great interest in March at the Motorscambio exhibition in Reggio Emilia and at the "Open Day" in Cambridge at the Cambridge Lambretta Workshop.

With great passion, great commitment and low resources.

Thanks to Franco, thanks to Nadia who saw her living room becoming a workshop and thanks to all the people that worked together with us believing in our dreams.

See you next time.

http://www.lambretta.it/twin/ing.htm