Ducati 350 Mark 3D

Desmodromic Emerges

The narrow case Ducati single cylinders were selling well and known worldwide through out the decade. Later in the decade when Ducati introduced the wide-case production models they represented the pinnacle of Ducati singles for the times. A single camshaft that was driven by bevel gears characterized the wide-case Ducati motorcycles.

As a direct descendent of the narrow-case family, the Ducati 250cc and 350cc versions of the wide-case models were first produced in the spring of 1968. The Ducati 450cc was added in the following year. The performance and elegant mechanics of the motorcycles immediately caught the attention of motorcycle enthusiasts worldwide.

Perhaps the most famous wide-case Ducati was the Scrambler. The Ducati Scrambler motorcycle sold tens of thousands around the world, leading to its legendary status. The fast and agile Ducati Mark 3 sports model was soon joined by the Ducati Mark 3D - the first Ducati with the now famous Desmodromic valve gear on a production model.

The word ‘Desmodromic' is not actually derived from Italian but rather from two Greek roots, desmos (meaning - linked) and dromos (meaning - track). The Ducati Desmodromic system is unique in that the valves are positively closed and opened by a cam and leverage system, rather than relying on standard valve springs. The same basic Desmodromic layout continues to win world championships today and is deeply seated in the Ducati Brand identify.

In 1968, the wide-case 350-cc Mark 3 Desmo was the fastest production Ducati one could buy, with 103 mph on tap, or 112 mph with a noisier megaphone pipe. There were several options: high touring bars instead of clip-ons and even a racing kit with more radical camshaft, fairing a range of main jets and megaphone exhaust.

The bike was unmistakable with early examples having twin filler caps on the fuel tank and the white-faced Veglia tachometer on the right fork crown. The fuel tank was chrome plated on the sides, with a metal Ducati badge, and the headlight and fenders were chrome plated.

When the 450-cc engine was introduced in 1969, the range was redesigned somewhat, with a square-slide Dell’Orto carburettor replacing the previous SS1, a single filler cap fuel tank and individual speedometer and tachometer, instead of the headlight-mounted speedo in the 1968 model. A cut-off Silentium exhaust silencer replaced the bullet exhaust.

Cycle magazine tested the 250-, 350- and 450-cc models imported to the U.S. and reported that the 250-cc and 450-cc engines had a wide power band, while the 350-cc was basically a bottle-rocket, with power coming on with a rush at 6,500 rpm. Not surprisingly, the 450 cc was fastest through a quarter-mile at 16.6 seconds, but the 350 did it in 17.6 seconds, and that was cut to 15.15 seconds with a megaphone exhaust, suggesting that the Silentium pipe restricted the bikes performance significantly.