Founded by brothers Adriano and Bruno Cavalieri as well as Marcello Ducati, what we now call “Ducati” first started out as “Societa Scientifica Radio Brevetti Ducati” back in 1926. The Bologna-based company got its start by manufacturing radio components, mostly for the Italian military. Unfortunately this made the company’s factory a target for being bombed in WW2 – something that would happen on several occasions. Around this same time another company known as “Societa Italiana per Applicazioni Tecniche Auto-Aviatorie” (or SIATA) started making small-displacement single-cylinder engines designed to be fixed to bicycle-frames. Supposedly due to the little single’s unusual exhaust note, the engines were dubbed the “Cucciolo,” or “little puppy”.
After WW2 had come and gone, Italy’s Institute for Industrial Reconstruction (or IRI) began managing SIATA and Ducati (and a lot of other companies). They opted to have the two companies join forces. So starting in 1950, Ducati would partner with SIATA to produce a 60 cc pushrod engine motorcycle. By 1953, Societa Scientifica Radio Brevetti Ducati was officially divided into two separate divisions: Ducati Elettronica SpA, and Ducati Meccanica SpA. The following year, Fabio Taglioni would step up into a position as Ducati Meccanica’s chief designer and technical director – a job he would hold until 1989.
In 1954, Taglioni would introduce the Gran Sport: a 98cc single with an OHC (overhead-cam) driven by a vertical shaft with conical gears, and a ten-degree forward tilt to the (nearly) vertical cylinder head. The Gran Sport would directly influence two-decades of engine development at Ducati. Then in 1956, the Gran Sport was revised and bumped up to a 125 cc double overhead cam (DOHC) setup. On an semi related note: Ducati’s history in the United States also began during this era. As the bikes won more and more races, they caught the attention of Joseph and Michael Berliner of the influential and powerful Berliner Corporation. The brothers would eventually go on to open the first US Ducati franchise.
Ducati’s Desmo system was born in response to valve float. To get decent power from a small displacement engine, high RPM’s are required, however the problem is when RPM’s are too high valve float is generated. Taglioni thought his desmodromic system could solve this, and he was right. Ducati’s 125 was first making 16hp at 11,500rpm, but after the introduction of the desmo system the same engine was putting down 19hp at 12,500rpm. This resulted in ridiculously short big-end lifespans, and crankshaft bearings supposedly had to be replaced after each race.
While you don’t really have to worry too much about super high-revving bikes on the street, the Desmo was a key part of Ducati’s plan to sell production road-goers. The brand wanted to establish itself as a “race-worthy” manufacturer, a feat that would give the company and its bikes a sense of legitimacy and prestige. The interesting part is that Ducati essentially accomplished this via utilizing technology from the 1800’s. The concept of mechanically forcing valves closed – instead of using spring actuation – was first conceived in the late-1800’s. The name “Desmodromic” comes from the Greek “Desmos”, meaning controlled, and “Dromos”, meaning course. Mercedes-Benz actually used Desmo technology in its W196 “straight-eight” Formula 1 racer in the ’54 and ’55 seasons, and Mondial also played around with the concept of a desmodromic engine in the early-‘50s but later abandoned the idea.
This high-revving 125 would go on to blow its competition out of the water, taking home its first win in 1956 at the Swedish GP at Hedemora while being piloted by Gianni Degli Antoni. Sadly, right as everything seemed to be on track, Antoni would lose his life during the practice rounds at the next race – the Italian GP of Monza. Ducati would start losing ground to MV Agusta, but in 1958 would bounce back, straight up dominating in competition and earning Ducati’s team a place in the World Championship. MV’s Carlo Ubbiali spent the season batting it out with Ducati’s Bruno Spaggiani, but unfortunately just as Spaggiani was getting the upper-hand in the overall standings, an unexpected injury would again throw a wrench in the plans of Ducati’s race department.
Ubbiali would ultimately take home the title that year for MV, but Ducati’s 125 had proven itself to the world as a competent racer. Ducati would further develop the 125 Sport via its release of the 125 Monza (and the British market-only Monza Super) before unveiling the 200cc Elite and 200SS, and then finally the 250cc Diana, Scrambler, and Apollo. Unfortunately, the Sport 100 wasn’t very popular outside of its native Italy and as a result would only see two years of production.
At the heart of the Sport 100 was an air-cooled, 98cc, four-stroke OHC single that made a reported 10hp at 8,500rpm. The Sport 100 came from the factory with a Dell’Orto MA18B carb, a four-speed gearbox with wet multi-plate clutch, and front and rear Amadori drum brakes. The 100’s chassis was a single tube open cradle frame in tubular steel. Suspension on the 1/10-liter scoot consisted of a Marzocci hydraulically damped telescopic fork in front while the rear suspenders were dual three-way adjustable units. Supposedly, the Italian single was good for a top speed of around 65 mph which sounds reasonable considering its dry weight of 220 lbs.
This particular 1957 Sport 100 example was privately imported into the US, and as the seller points out: “this is not a common pushrod Bronco but a hard to find overhead cam model.” Aside from the seat, everything on this example appears to be stock, though perhaps someone more knowledgeable than myself can confirm or correct this in the comments below. It’s not exactly a museum quality example, but it’s nonetheless a pretty clean one, especially for being six decades old. This bike has a clean California title, as well as its original 1958 Italian title.
You can find this 1958 Ducati Sport 100 for sale here on Craigslist in Tarzana, California with a price of $4,750.