Ducati 350 and 500 GTL and Sport Desmo servicing
1975 to about 1983 · 350cc and 497cc chain-driven SOHC parallel twins · Greenwich, London
Ray Petty Meccanica services, repairs and restores Ducati's 350 and 500 parallel twins, the GTL, GTV and Sport Desmo of 1975 to the early 1980s, at its independent Ducati workshop in Greenwich, London. These are the odd ones out among classic Ducatis, with a chain-driven camshaft and a 180° crank, and RPM treats them on their own terms.
About the GTL and Sport Desmo
Ducati's parallel twins took over from its singles in the mid-1970s. The 350 and 500 GTL, styled by Giorgetto Giugiaro, appeared in 1975 with a single overhead camshaft driven by chain, two valves per cylinder, a forged 180° crankshaft on plain bearings and a five-speed gearbox. The 497cc (78 x 52mm) 500 used 30mm Dell'Orto carburettors and the 350 used 26mm ones, with battery, coil and points ignition and a Bosch electric starter. Fabio Taglioni then designed Desmodromic heads for the 350 and 500 Sport Desmo, which Leo Tartarini styled and which used a twin-downtube frame. The GTV put the GTL engine in Sport Desmo clothes. Sales were slow, and leftover engines kept production going into the early 1980s.
Servicing your GTL or Sport Desmo
Unlike the bevel twins and the belt-driven Pantah, these engines drive their camshaft by chain. GTL and GTV heads use conventional valve springs, while the Sport Desmo has opening and closing clearances to check. Oil deserves more attention than usual: the factory called for changes every 5,000km, and oil feed to the camshaft is recorded as a weak point, so fresh oil at the right level matters. The contact breaker points sit behind the left cylinder and are awkward to reach, and with starting reliant on the electric starter, the battery and charging need to be healthy. RPM sources parts for these less common twins and calls the owner to agree the work first.
Book your GTL and Sport Desmo in
Tell us what it needs, or how long it's been off the road, and we'll take it from there.
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Saturday: 10am to 5pm
Sunday and Monday: closed