DUCATI REGOLARITÀ
A Ducati stroker? Excuse me? Are you serious? Alan Cathcart explains a little-known endure Ducati…
A Ducati stroker? Excuse me? Are you serious? Alan Cathcart explains a little-known endure Ducati…
Lots of famous makes have skeletons in the cupboard, models they’d rather you didn’t know they ever made. Like the 50cc moped and 98cc scooters that MV Agusta produced back in the 1950s, or Moto Guzzi’s threewheeled delivery truck – or indeed the smallest Norton ever sold, the overweight, unreliable Jubilee 250 twin, whose copious oil leaks stained many a British driveway. Or – but you get the picture. So how about the last-ever Ducati single-cylinder streetbike, of which 3846 examples were built from 1975 to 1979, which was also incidentally the first Ducati motorcycle to be built with a left-foot gearchange? It wasn’t just that it was the 125 Regolarità and its later Six Days variant represented the Bologna factory’s only serious attempt to target the off-road market, but it was that contradiction in terms – a Ducati two-stroke!
It’s true that, like the dozens of other Italian makes trying to carve a slice of the country’s huge appetite for affordable personal transportation in the 50s and 60s, Ducati had earlier made several eminently forgettable 50-100cc two-stroke models, from the Brio scooter to the Rolly moped, the Mountaineer high-handlebar commuter to the Brisk single-speed runaround, whose names alone defied all known truth-in-advertising regulation, yet which collectively represented the major part of Ducati production in the 1960s.
But by 1975 when the 125 Regolarità was launched, Ducati had moved
on, and was now well established as the leading Italian four-stroke performance brand, with a twin-cylinder sportbike range derived from Paul Smart’s V-twin Imola 200-winner. The idea that it should have tried to carve out a slice of the then-booming 125cc enduro market for sixteen year-olds, a market populated by 23 other makes, seems very – well, shortsighted, let’s say.
Mind you, bureaucrats have never been much good at running bike companies, and since 1967 Ducati had formed part of the Italian government’s EFIM state-owned conglomerate responsible for the dayto-day operations of the company and 114 others within Italy. However, it had the good fortune to see Fredmano Spairani appointed as its CEO in 1969, a professional manager with an open mind as well as some flair, who listened, learned and acted on what he was told. Fabio Taglioni and his colleagues convinced Spairani of the values of a product-led strategy based on the large capacity 750cc four-strokes that BSA-Triumph and Honda had just launched, underpinned by a factory race programme, and that’s how the family of 750cc V-twin Ducatis came about.
Unfortunately for Ducati, Spairani’s success in spearheading the company’s transformation meant he was appointed in 1973 to try to pull the same trick on Agusta’s aviation and motorcycle business, which had also fallen under EFIM control – and his elderly, short-sighted successor Cristiano de Eccher was only concerned with numbers, not product. So
at his specific behest two new model platforms targeted at volume market segments were created, and are today regarded as eminently forgettable postscripts of Ducati history – the 350/500cc parallel-twins, and the 125 Regolarità two-stroke Enduro.
Italo Forni was Italy’s star off-roader of the 1970s, a multi-time Italian MX and Enduro champion in the 125/250/500 categories, and at various times a works rider for Honda, KTM, CZ, Montesa, Kawasaki (he was the first European rider to be signed by the Japanese factory), Moto Villa (for whom he won 36 races in 38 starts in 1972) – and Ducati. Today an active 69-year old who’s enjoyed a series of key roles in the Italian bike industry since retiring from racing in 1980, Forni was the man Ducati engineers recruited back then to help them develop a product for a market sector they had no experience of at all, but which de Eccher had insisted must be addressed in Ducati’s catalogue – a street legal 125cc enduro dirtbike.
‘Ducati contacted me in 1973 to ask them to help develop an Enduro,’ recalls Forni. ‘So I went to Bologna to meet Taglioni and Cosimo Calcagnile, the Commercial Manager. Taglioni had designed an all-new single-cylinder fourstroke engine to replace the wide-crankcase Mark III singles which were just then ending production, and he’d wanted to use this to develop a range of 250 and 350cc bikes for the Enduro market, to follow on from the successful Scramblers. Spairani had been favourable to this idea, but the new guy refused to consider it – he considered himself an expert on the market, and that meant it had to be a 125 twostroke, because that was what everyone else was selling.
Never mind about Ducati’s inexperience in this sector, or the reduced profit margins in such a competitive marketplace! So Taglioni and his colleagues in the Reparto Sperimentale decided to use the bottom half of that new fourstroke engine, but to fit it with a two-stroke top end. Since they neither knew nor cared much about two-strokes, they simply used the most successful engine in the sector as a reference, which was the Sachs. That’s why the Ducati twostroke has the same radial cylinder head finning as the German engine, why the crankcase is very wide and heavy for a 125 two-stroke, and why the crankshaft and transmission are also overdimensioned – they were designed for a bigger four-stroke engine! People always thought this was because Ducati planned to make a future 250cc version possible – but I assure you that was never the intention!’
Launched in April 1975, the 125 Regolarità had an air-cooled piston-port motor with ‘square’ 54x54mm dimensions, originally with four transfer ports and a single exhaust in the Gilardoni cylinder’s cast-iron sleeve, then later with twin additional boost ports. Fitted with a 30mm Dell’Orto FHB carb, and running a high 12.4:1 compression after the 10.5:1 ratio the bike was launched with had to be raised to give a
much needed boost in acceleration, the engine produced 21.8bhp at 9000rpm at the gearbox. This was comparable with the competition, but with a narrower powerband compared to the Sachs motor it had attempted to copy. Maximum torque of just 16 Nm was delivered at 8000 revs.
The heavy duty six-speed gearbox and oilbath clutch – remarked on by contemporary testers as ‘quite capable of harnessing more performance from a larger capacity engine’! – were needed to coax all available performance from the engine. The 109kg dry weight was heavy by class standards, ten kilos more than most of its competitors, and there was a battery behind the left side numberplate to power the small headlamp with its sexy-looking but heavy steel grille (the detachable air filter was neatly housed on the opposite side). The Motoplat CDI, running 19° advance, had a flywheel generator that ensured the Ducati two-stroke motor could run without the battery, meaning the exposed ignition key on the left side was only needed to turn on the lights. It seemed strange that Ducati needed to import the new bike’s ignition system all the way from Spain, rather than sourcing the equivalent from its Ducati Elettronica sister company just down the road – unless it was the fact that Sachs used a Motoplat CDI, too...
The Ducati’s twin-loop Verlicchi mild-steel frame was surmounted by a slab-sided six-litre plastic fuel tank filled with 5% mixture, which proved to be on the small size once magazine tests revealed a thirsty 38mpg – high for a 125 enduro. The 35mm Marzocchi forks offered 180mm of wheel travel, with a box-section steel swinging arm with twin Marzocchi piggyback air/oil shocks. These featured remote air chambers running 2.0kg/cm² pressure, fiveposition spring preload adjustment, 130mm of wheel travel, and a choice of three upper mounting positions.
The routing of the fat Lafranconi exhaust (with detachable rear section to allow for repacking baffles) beneath the engine was a real handicap, says Forni. ‘At the direction of the management, the first version of the bike was really more of a streetbike than a competition enduro model,’ he says. ‘But Ducati owners love to race, even on a two-stroke, so it soon became obvious there were several changes we’d have to make to reflect this.’ Yet the tiny 125mm Grimeca single leading-shoe drum brake fitted to the 21” front wheel was definitely undersized for street use, especially with a passenger, even when its 140mm rear companion on the 18” wheel was used hard – and with a class-leading top speed of 119kph in independent tests, the 109kg Ducati needed some stopping.
However, the Akront alloy rims, Magura handlebar and levers, Aprilia switchgear and headlamp, Preston Petty flexy plastic mudguards with a small zip-up documents pouch on the rear one, Arieto numberplates and Nino Verlicchi spring-loaded footrests, were all quality components on an entry-level bike that was somehow competitively priced.
In order to gain some two-stroke credibility with potential customers, Ducati supported various Regolarità riders in local Enduros and in France, the only other country the model was catalogued in. That extended to the 1975 ISDT in which the test bike competed, but success was slow in coming. Italo Forni was thus hired by the factory to race the Regolarità in the 1976 Italian MX and Enduro championships, as well as in the ISDT in Austria – in the course of which he developed an uprated version which Ducati introduced for 1977 under the ‘Six Days’ label, replacing the previous model.
Boasting more aggressive off-road styling with an 8-litre aluminium fuel tank and blackpainted motor, the new bike came in two versions, Cross and Regolarità, each with revised porting for the new chrome-bore cylinder and altered ignition timing, which coupled with a new design of combustion chamber and piston with more squish, a larger 32mm carb, and compression raised to 14.6:1, delivered a healthy claimed power increase to 25bhp at 10,250rpm.
The weight issue was addressed via a chrome-moly frame, magnesium sliders on the Marzocchi forks, and measures such as a much
lightened steel clutch basket shot full of holes to combat the kilos, down from 1.32kg to 0.98kg. Dry weight was slashed to a claimed 99kg, which actually turned out in magazine tests to be 104kg, but the front brake was increased to 140mm in size, and most important of all the exhaust was rerouted to run up and over the top of the cylinder, exiting under the seat on the left. The price was however raised to a more realistic level that was comparable with the competition – it’s doubtful that Ducati made much profit out of the 2786 examples of the Regolarità it made and sold in 1975-76.
‘The Six Days was a much more competitive mount,’ says Italo Forni. ‘It had an improved riding position because of a better shaped fuel tank and the tucked in exhaust. However, it was still rather fragile, and was quite highly stressed to deliver competitive performance, although by the middle of 1977, we’d begun to win races with it. But the sales had failed to meet expectations, so just as we had it coming good, EFIM decided to end the project.
‘The original Regolarità model had lost Ducati credibility, by giving the impression it didn’t know or care about Enduros – which was indeed partly true. It was born out of a compromise, because the EFIM management wanted to have a streetbike that their 16-year old customer could ride to the café with his girlfriend sitting behind him, yet could also win races. And in the 1970s 125cc off-road sector, that didn’t happen, because there were some very specialised rival products. It was too bulky, and too heavy to ride – indeed, it was quite old-fashioned even by mid-70s standards. It had a very peaky
power delivery because to get the necessary engine performance they had to narrow the powerband, so there wasn’t much torque, which in Enduro is a problem.
‘It was actually better as a motocrosser, once we started removing weight, and those were the races I won on the bike before they closed everything down. Ultimately, it had everything it needed to be successful, but it just wasn’t thought through properly at the beginning. This was probably because Taglioni hated twostrokes and resented being forced to produce this model.’
Still, that wasn’t the end of the Ducati Regolarità story. In 1979 the defunct engine project was acquired from Ducati by Leopoldo Tartarini, the owner of the Italjet factory at San Lazzaro di Savena, on the other side of Bologna from Ducati’s Borgo Panigale base. He’d raced for Ducati as a factory rider in the 1950s, before undertaking a remarkable 13-month roundthe-world trip in 1957/58 with a colleague on a pair of 175cc Ducati singles, a trip which brought the marque untold publicity that helped it stand out from its dozens of competitors just as it was getting established as a sporting brand.
By the late 70s, Tartarini’s talents for building good-looking, fine-handling bikes of all capacities under the Italjet label – most notably the acclaimed Triumph Bonnevilleengined 650 Grifon – were well established, leading to a close collaboration with Ducati. He designed all the Mark III singles, including the iconic Scrambler, as well as Taglioni’s new range of 750cc V-twins, most notably the iconic 750SS green-frame desmo Imola replica. The lean, cobby looks of this most desirable of bevel-drive Ducatis were entirely owed to Tartarini, a self-effacingly modest forerunner of Massimo Tamburini and Pierre Terblanche, who could ride as hard and as well as he wielded a pencil.
‘Ducati in those days were mainly engine manufacturers,’ Tartarini explains. ‘ They had no design studio and only a very limited production capacity for complete motorcycles, because they were too busy building diesel engines for automotive and industrial use alongside the bikes. Because of my earlier connections with the firm, Italjet was called on to design not only the street singles, but all the early Ducati V-twins, based on Ing. Taglioni’s engine and chassis layout. Then, later in the decade, we not only designed the frame and the styling for the range of Ducati paralleltwins, but actually manufactured the bikes ourselves in the Italjet factory, using engines trucked across town from Ducati.’
This close relationship, and the demise of the Enduro project, meant that Italjet was able to acquire the 125cc two-stroke engine design in all its various forms from Ducati, badged with its own name for use in various models – and doing so neatly squared the circle for company boss Leopoldo Tartarini. ‘I was aware of the Regolarità’s engine from its four-stroke origins,’ he explains. ‘So I knew it had a very strong bottom end design that was
capable of handling a lot more power, whether two-stroke or four-stroke in derivation, in the category I wanted Italjet to attack – this was the Trials sector, that was then gaining fast in popularity. So early in 1979 I acquired all the Regolarità’s engine drawings and patterns, and modified it to produce three new engines all using the same Ducati 125cc base: a 350 twostroke, a 250 two-stroke, and a dry sump 350 four-stroke with a single overhead camshaft that delivered 38bhp. I used this in the Italjet Scott trials bike that debuted in 1983, of which we made about 100 examples. Taglioni was especially pleased to see this, because it represented the form in which he had always intended the engine to appear.’
However, three years before this 322cc fourstroke version that was more of a trailbike than a trials bike appeared, the 250cc/350cc two-stroke variants had made their debut in Italjet’s distinctive bright green Trials models which debuted in 1980 alongside a pair of Minarelli-powered 50/125cc models. Italjet had previously been the Italian importers for Bultaco, for whom American Bernie Schreiber had won the 1979 World Trials Championship, but with the Spanish firm bankrupted by rising debt and political uncertainty, Schreiber moved to Italy to develop the new Italjet bikes. He finished second to Montesa’s Ulf Karlsson in the 1980 World series on a 326cc version powered by a larger capacity version of the 6-speed Ducati-based engine. A smaller 237cc version was also developed, and both offered for sale, with around 1000 examples built and sold, according to Tartarini.
For 1981, Italjet produced an improved, lighter version, of the T350, but Schreiber could only finish sixth in the World Championship, and his move to the rival SWM concern marked the end of Italjet’s world series involvement.
It was also the end of the road for the Ducati two-stroke project. This can only be characterised as confused, having started out as a four-stroke, entered production as a two-stroke, then given away for adoption like a problem child to a satellite company that actually did
OK with it in the end. And in doing so, it actually ended up coming home – because it was Italjet boss Leopoldo Tartarini who designed the original 125 Regolarità for Ducati!
‘I did it over a long weekend late in 1974,’ recalls Leopoldo. ‘And the man who helped me design it was Joe Berliner, Ducati’s American importer. At that stage there was a chance that he might import it into the USA, where the two-stroke Enduro market was now an important market sector, so he worked with me in styling it. He was very intelligent and passionate about design, maybe surprisingly so for such a hard-headed businessman. In the end they decided just to concentrate on the V-twins – but we created the Regolarità together!’
But that’s not quite the end of this multifaceted story. As Italo Forni recounts, in 1975 he and Ducati R&D engineer Franco Farnè developed a four-stroke Enduro model for Ducati’s Spanish affiliate Mototrans, complete with disc brakes, monoshock frame, and an all-new 500cc bevel-drive sohc engine which Taglioni had produced, using many parts and much technology from the 864cc version of the V-twin engine that was by then in production. This four-stroke Enduro was conceived one year before the XT500 Yamaha appeared, which duly became the class benchmark, and was apparently a very small, light, advanced design not much bigger than a 125 Husqvarna.
‘We built two prototypes which went to Spain, but the reason it never entered production was because of Mototrans closing down,’ says Forni. ‘ This was a very good bike which pre-dated the arrival of the four-stroke Enduro boom. Ironically, the EFIM guy who insisted that Ducati should build an Enduro bike got it right, but he should have let Taglioni do it the Ducati way and build a four-stroke, in which case they would have led the world!’
If only…