Text and Photos : José Manuel Serrano Esparza
AN AMAZING POWERPLANT WITH 1 LITRE / 100 KM CONSUMPTION
In 1948 (two years after the introduction into market of the original 48 cc Cucciolo 1, designed by Aldo Farinelli and Aldo Leoni as a four-stroke with over head valves, two speed gears and chain drive small engine to be attached to pedal bicycles and which sold well from 1946, manufactured by Ducati under S.I.A.T.A — Società Italiana Auto Trasformazioni Accesori, based in Turin— licence, at a period in which vast majority of the other clip-on engine assemblies from other brands were mostly two strokes), Ducati decided to utterly redesign the Cucciolo 1, creating the Cucciolo T2 engine. designed by the Chief Engineer Giovanni Fiorio and the first project tackled by Ducati in the motorcycle engine sphere, that featured a number of advantages over its predecessor:
- A modified cylinder head.
- The oil filters are in a different position.
- A more stalwart structure of both metallic components and assembly groups.
- A more accessible drive mechanism.
- A superior powerplant performance.
- A raised rating.
- A revamping of the single cylinder, which was made removable.
- An increase in power.
- The engine was cantilevered.
- The crankcase splits in a different way.
- A first-string reliability in comparison to the Cucciolo T1 that was a bit temperamental and sometimes suffered from overheating.
The gorgeous 48 cc Cucciolo T2 engine, a masterpiece of engineering precision and miniaturization, which already in late forties and early fifties epitomized the love for the product, optimized performance and obsession for perfection that has since then been Ducati´s raison d´etre. On top we can see the valve operating rods painted in black, the intake being grasped by Enea Entati, and behind it are the crankcase cylinder and cylinder head, both of them made with aluminium alloy and heavily finned for efficient cooling. The cylinder is detachable from the crankcase, which simplifies the inspection, decarbonizing, valve grinding and reboring.
And in the lower area of the cylinder runs the three-ring aluminium piston — here in down position — with oil scraper ring (inside an iron sleeve onto which the alloy finning of the cylinder is diecast), linked by a steel connecting rod running on needle rollers to the crankpin, which is held between two cranks running on ball-bearings.
Enea Entati making the three-ring aluminium piston go to its up position in the lower area of the cylinder.
On its turn, the middle and lower area of this side of the Cucciolo T2 engine is occupied by the crankcase (complete with bearing races, washers and tapped guides) and reveals the two-speed gearbox system transmitting the primary drive from the crankshaft pinion through the cam driving gear to the multiple metal plate clutch, then through the mainshaft gear pinions to the lay shaft pinions, with the inner end of the lay shaft being the bearing spindle for the single profile cam and the cam gear, and the outer end of the key shaft passes through the crankcase casting and carries the driving sprocket. This way, the two cogwheels visible are the driven sprockets for first speed and second speed.
Enea Entati grabbing the Ducati 48 c.c Cucciolo T2 engine unit made in 1949 beside Gianfranco Zappoli, Head of the Ducati Office of Mechanical Works and a world class authority in bike engines mechanics and motion physics along with the energy aspects related to the transformations involving thermal phenomena in engine operation. Gianfranco Zappoli has worked in Ducati for 43 years and features more than thirty years of experience in the production departments of Ducati. He is presently the Secretary of the Ducati Historical Register and likewise a remarkable expert in motorcycle engine efficiency resulting in less consumption, as well as having implemented a very important and praiseworthy teaching labour as a Technical Head of the Ducati Physics Laboratory in Moto.
Emotions run high while living legends of Ducati History surround the landmark Cucciolo engine.
From left to raight :
- Enea Entati, collaborator of Ducati Group as a skilfull restaurator of classic and vintage Ducati motorcycles.
- Giuliano Golinelli, avid Ducati motorcyclist boasting an experience of twenty years as a restaurator specialized in Scrambler models as well as being a Ducati collaborator in the historical register.
- Gianfranco Zappoli, in Ducati since 1973 when he began as a worker until becoming plant engineer and subsequently turning into an internationally recognized authority in motorcycle engines efficiency, being at present Head of the Ducati Office of Mechanical Works and Technical Head of the Ducati Physics Laboratory in Moto, in addition to being a frequent guide in the tours to the Ducati Borgo Panigale factory in Bolonia).
- Gianluigi Mengoli, in Ducati since 1970, Director of Ducati Research and Development and current Honorary President of the Ducati Historical Register, father of the Desmoquattro powerhouse along with Massimo Bordi and designer of many of the most famous powerplants for Ducati bikes, among them the mythical 90-degree V-Twin Ducati Pantah with the genius Fabio Taglioni in 1976, the Desmoquattro Ducati 851 — which pioneered the use of four valve heads, liquid cooling and computerized fuel injection in the company´s twin cylinder engines— and Ducati 888 engines in 1987 and 1991 respectively, with the Desmoquattro valvetrain concept bringing about a four valve per cylinder engine working through desmodromic valves in synergy with cams opening and closing them, with four rockers placed between the camshafts to improve the port design and with which Ducati would start its halcyon days in SBK, managing to win the record figure of 15 Superbike World Championships between 1990 and 2011, the Monster 1000 Dark and 1000 S engines in 2003 with increased power and optimized cooling as defining parameters, being nowadays the greatest authority on desmodromic valve control systems and efficient combustion chambers and one of the most relevant personalities in Ducati History, together with Mario Recchia, Fabio Taglioni, Franco Farné, Massimo Bordi, Massimo Tamburini, Pierre Terblanche, Miguel Galluzzi, Giandrea Fabbro, the Ducati living encyclopedia Livio Lodi, etc).
- Giuseppe Di Marco (in Ducati since 1976 and a man who saved a lot of corporate historical material in all sectors).
- Isa Baraldi (Enea Entati´s wife and also a Ducati heartfelt enthusiast).
This wise and visionary entrepreneurial decision by Ducati of designing the new Cucciolo T2, strongly inspired by the Cucciolo 1 and its two-speed gearbox drawing the full potential of the powerhouse and primary transmission by gears, but providing the aforementioned highly significant upgradings, proved to be a key movement for the future of the brand,
The British specialized motorcycling magazines recognized the superior level of engineering, reliability, fuel efficiency (1 litre/100 km !), quality of materials, maximum speed of 40 km/h and top-notch mechanizing of the Cucciolo T2 and hailed it as the best cycle attachment engine in the world.
The international success of the single cylinder 1.5 H.P at 5.500 rpm Cucciolo T2 engine was so big that Ducati also launched into market a 2 H.P sporting version, able to reach a top speed of 60 km/h.
A HOST OF ACCOMPLISHED FEATS
Besides, the 48 cc Cucciolo T2 engine also gained a deserved international fame thanks to feats like:
- The victory of the Ducati pilot Mario Recchia in the Viareggio Circuit race on February 15, 1947, with a Cucciolo engine adapted to a bicycle.
- The world record of speed in the 50 c.c category achieved by the Italian pilots Tamarozzi and Zitelli in Monza Circuit in 1950.
- The travel in Australia in which Rene Joseph Bregozzo rode 631 miles on a Cucciolo T2 attached to an Advance push-bicycle from Sydney to Melbourne with only 2 3/4 gallons of gasoline.
- The world record of uninterrupted march with 48 cc engines, working flawlessly for 47 hours and 10 minutes, attained at the sports facilities of Ferrocarril Oeste, Buenos Aires (Argentina) in 1949.
- In late 1949, a bicycle with a 48 c.c Ducati Cucciolo T2 engine won the Australian Tour of the West A class competition, covering 1050 miles within the inner New South Wales State between the towns of Dubbo, Narromine, Tullamore, Peak Hill, Parkes, Forbes, Orange, Bathurst, Lithgow, Capertee, Kandos, Mudgee, Dinedoo and Mendooran, on gruelling roads filled with creeks, ridges and irregular ground without any problem and less than 4 gallons of petrol.
- In January of 1950, Ernesto Che Guevara made his first travel across Argentina after attaching a 48 c.c Cucciolo T2 engine to his bicycle, going from Buenos Aires to San Francisco (Córdoba), Córdoba capital, Santiago del Estero, Tucumán, Salta, Catamarca and La Rioja, and coming back to Buenos Aires across San Juan, Mendoza and San Luis, it all without any powerplant failure.
Detail of the timing system of the 48 cc Ducati Cucciolo T2 engine where we can see the pull rods and superior arms that in symbiosis with the inferior arms make the tiny overhead two valves (placed just under the valves springs)
work with amazing accuracy, setting up a system in which the valves are driven through linkage and rocker arm.
Here is an enlargement of the sturdy springs of both valves, which are located under them. The valve timing features a clearance of 6/1000th of an inch between valve stems and operating arms, in such a way that the inlet valve opens between 5 degrees and 15 degrees before top dead center and closes between 25 degrees and 30 degrees after bottom dead center, whereas the exhaust valve opens between 45 degrees and 35 degrees before bottom dead center and closes between 0 degrees and 20 degrees after top dead center, always understanding that in a four-stroke engine inlet timing accuracy is more important than exhaust timing, because the outgoing gases look after themselves, albeit the Cucciolo T2 features a very good mechanism of two cams fixed in relation to each other that makes both exhaust timing and inlet timing work like a charm.
A MILESTONE POWERPLANT DESIGN IN THE HISTORY OF MOTORCYCLING STEMMING FROM ITALIAN HUGE TALENT AND INGENUITY WITH VERY FEW MEANS
The 48 c.c Cucciolo T2 engine meant an innovation in the field of motorcycles, because nobody had ever before had the dazzling idea of applying a propulsion motor to a bicycle.
And from a historical viewpoint, it is a wonder of traditional mechanics featuring incredibly smooth start and halt thanks to its prime multiple metal plate clutch running in oil bath in the crankcase, besides delivering awesome performance and reliability for such a small and light powerplant (its weight was 8 kg) and being so simple to operate, with just two levers, a very well devised gear transmission system substantially rooted in Leonardo da Vinci´s 1490 stepless continuously variable transmission concept, the throttle and clutch making work the powerful 2-speed gears and foolproof automatic change.
Furthermore, its positive chain drive resulted in no extra wear in tyres, ensuring maximum power and positive non-slip traction, with the added benefit of avoiding any wobble once the Cuccilo micromotor was fitted to the cycle bottom bracket, so perfect balance was retained.
The single-cylinder four-stroke 48 cc Cucciolo T2 engine features a maximum power of 1.5 HP at 5.500 rpm and bore x stroke of 39 x 40 mm and proved to be an important tool in late forties and early fifties to solve the transport needs of many people in the five continents, in an exceedingly cheap and practical way, transforming their bikes in motorcycles, and any person was able to adapt this micromotor to his / her push-bike using pliers and a screwdriver.
In addition, its four-stroke nature makes that no oil has to be mixed with fuel, since engine lubrication is fully independent and automatic, so refuelling is simple and fast.
On the other hand, the Cucciolo T2 sports chain transmission. This way, the bicycle chain is used for the drive, which reduces wear on tires to a minimum and prevents wheel-spokes from braking and any possible twisting of frame, as well as featuring a two-speed preselection gearbox whose ratio enables to negotiate uphill gradients up to 18% at speed without the aid of pedals, with the adequate back sprocket ratio.
It also excels in its efficient cooling provided by a number of slots and fins where the airflow is maximum.
And whenever it was put through its paces, the Cucciolo T2 engine performed seamless, whether in streets, normal roads, A-class races or hillclimbs, thanks to its four-stroke torque qualities that begot a major advantage over the two-stroke powerplants of the contending bikes from other brands.
Moreover, the smaller than normal multi disc clutch of the Cucciolo T2 results in a quicker acceleretaion and deceleration of this engine, in such a way that you can drive the motorized bicycle deeper into the turns and have the powerplant rpm drop quickly, and on accelerating out of a turn, the engine is able to reach peak rpm faster than with a heavier clutch, and the reduction on discs diameter is compensated by the greatly increased total area of the surfices provided by the multiple discs to hold maximum feasible power, gaining smoother engagement and attaining even more force.
Ducati Cucciolo bicycle petrol tank with capacity for two litres and an autonomy of 200 km, with the added bonus of an automatic reserve supply always available from the right lower part of the tank, which should the machine run out of petrol, a slant of the bicycle to its left side would transfer this extra fuel to the tap side, allowing another 5 or 10 miles running of the 48 c.c Cucciolo T2 engine.
Complete Cucciolo T2 engine attached to an original Ducati Cucciolo bicycle. Now the powerplant is complete with the crankcase cover, the magneto flywheel with the word Cucciolo engraved on it, the carburettor body with Weber 14 MFC on the right of the induction pipe, and the exhaust pipe with low pressure silencer on the right of the lower area of the crankcase cover.
Detail of the magneto flywheel, whose mission is making the ignition rotating at 1/1 ratio with the crankshaft and also to produce 6 volts electric current through its lighting coil when the engine is running, enabling the illumination of both the bright headlight and tail light thanks to its 12 watts generator.
Detail of the small tank for lubrication, with a capacity of half a litre of oil carried in the bottom of the crankcase.
Aerial view of the Cucciolo T2 engine attached to the frame of the original Ducati Cucciolo bicycle.
Detail of the Weber carburettor with 14 mm choke of the Cucciolo T2 engine. It features a single lever automatic operation and is flange fitted to the induction pipe. Two jets ensure easy starting, smooth running and economy at all engine speeds. The carburettor has two adjustment screws: A to adjust the ratio of petrol to air for idling mixture and previously adjusted at the factory for normal running, and B, which is simply a stop to prevent the full closing of the butterfly valve and makes possible that the speed of idling can be adjusted.
© Text and Photos: José Manuel Serrano Esparza
