Ducati’s second-generation v-twin engine – the 900cc ‘square case’ (actual capacity 864cc) – debuted in the 860GT of 1974 and the following year was used to power the new 900SS superbike.
The latter was styled like the original 750SS that had been developed from Paul Smart’s 1972 Imola winner. (The 750SS continued in this new ‘square case’ guise, though almost all of these smaller, second-generation models were destined for the Italian market). More than just a simple over-bore, the ‘square case’ engine incorporated a new camshaft drive arrangement, improved oil pump, cartridge-type oil filter and electronic ignition. In addition, the gearchange was moved to the left-hand side and the frame altered to provide chain adjustment at the swinging arm pivot. As had been the case with the original 750SS, desmodromic valve gear distinguished the new sports roadster from its tourer counterpart. ‘Like the tamer valve spring version of the engine in the 900GTS it is uncannily smooth, while possessing a much more dramatically punchy power output than the soft touring motor,’ reported Bike magazine in October 1977. Breathing through gaping 40mm Dell’Orto carburettors, the 900SS engine produced 70bhp at 7,500rpm, an output good enough for a top speed of 135mph. The 900SS’s competition heritage was obvious on the road: ‘While other flash Italian bikes are basically roadsters dressed up and pretending to be racers, this is the real thing,’ declared Bike.
Engine design improvements pioneered on the Darmah model were incorporated for 1978 together with a left-side gearchange, while Speedline alloy wheels were adopted part way through the year. For 1981 the 900SS underwent more extensive updating, gaining improved cylinder heads, Bosch ignition and – later on – a revised gearbox. Production ceased during 1982 after a little over 6,000 had been produced and today this classic Ducati bevel-drive twin is highly sought after.
This particular 900SS was kept by its first owner until May 2013 and is currently in the hands of only its third registered keeper. We are advised that no work has been carried out on the machine since its acquisition in June 2017. Described by the private vendor as un-restored, the machine comes with a substantial history file containing numerous bills, a quantity of MoT certificates and tax discs, and old/current V5/V5C registration documents.
Report by bonhams.com