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Italian Motorcycles

Ducati Parallel Twins


"500 bicilindrico GTL, uno dei modelli meno popolari dell’intera produzione Ducati. Nato come progetto esterno alla fabbrica di Borgo Panigale per mano della Ricardo, quella dei bicilindrici paralleli fu una scelta imposta dalla gestione statale dell’epoca che non incontrò mai il favore dell’Ing. Fabio Taglioni.

Tanto per darti un’idea della reputazione che questa moto aveva, basta citare i soprannomi che gli erano stati dati a quel tempo: demonio e frantoio. L’autonomia massima di questo tipo di motore era, infatti, di circa 5.000 Km, dopo di che cominciavano i problemi.

Nonostante tutto, Taglioni cercò di salvare il progetto attraverso l’adozione del comando desmodromico della distribuzione e Leopoldo Tartarini disegnò una nuova linea, più simile al Darmah, con cerchi a razze invece che a raggi. Anche questi sforzi, però, furono vani e in pratica i bicilindrici paralleli decretarono il fallimento della Mototrans. Ad ogni modo, di modelli ne sono stati fatti diversi: il primo, il 500 GTL con avviamento elettrico, è stato prodotto dal 1975 al 1976 in 930 unità. La versione di 350 cc, invece, è stata prodotta dal 1977 al 1981.

La variante Sport desmo fa la sua comparsa nel 1977 e rimane in listino fino al 1981, sia nella versione di 500 cc che in quella di 350 cc. I colori previsti erano: verde e nero con banda oro per la 350 GTV (quella disegnata da Tartarini), blu per la 500 GTV. La 500 Sport Desmo era proposta in livrea rossa con banda bianca, mentre quella della 350 era gialla con banda nera. Il primo 350 GTL era blu (con singolo disco anteriore, mentre sui modelli successivi c’è un doppio disco), invece il 500 veniva commercializzato in verde inglese con strisce bianche."


GTL500, GTV500, SD500 and 350cc Models built by Ducati Italy and MotoTrans Spain.

"500 twin cylinder GTL, one of the least popular models of the entire Ducati production.

Born as a project external to the Borgo Panigale factory on the drawing board of Ricardo, the parallel twin was a choice imposed by the state management of the time which was not favoured by Ing. Fabio Taglioni. To give an idea of the reputation this bike had, the nicknames given to it at the time: devil and crusher (demonio e frantoio).[1] In Australia, it was known as the paralysed twin. The maximum life of this type of engine was generally about 5,000 km, after which problems began.

In spite of everything, Taglioni tried to save the project through the adoption of a desmodromic head, and Leopoldo Tartarini designed a new line, more like the Darmah, with cast wheels instead of spoked.[2] These efforts did not bear fruit and in practice the parallel twin was decreed a failure by Mototrans.

Several models were produced: the first, the 500 GTL with electric starter, was built from 1975 to 1976 (930 units). The 350 cc version of this was produced from 1977 to 1981. The Sport Desmo variant appeared in 1977 and remained in the catalogue until 1981 in both 350 and 500cc versions.

Colour Schemes

Green and black with gold pinstripe for the 350 GTV (the one designed by Tartarini), blue for the 500 GTV. The 500 Sport Desmo was presented in red livery with white bands, while the 350 was yellow and black. The first 350 GTL was blue (with single disc brake, with the following models sporting dual discs), and the 500 was marketed in English green with white stripes."

Source: Valerio Borghese, quoting from an older Italian magazine article.

Notes
1. "frantoio" is the oily and noisy machinery which is used to press olives to make olive oil, so it means an engine with some serious problems!
2. The original cast wheels on the SD500 were by Speedline, and tended to self-destruct. The following gives insight:

  • "According to Bob Brown, they dont like a thrashing, he told me that Mike H when he visited Melbourne (all those years ago) borrowed an SD500 from his shop and retunred it completely effed. At least MH rode one!

    In order to reduce the possibility of self destruction I believe a larger base gasket on the barrels reduces the comp ratio, again that is advice from Bob Brown. Mine is standard and still running fine.

    The original (I think it was speedline) wheels, they are a greenish gold colour were a problem. On my first SD500 the front split! The replacement wheels which came later appear quite strong if heavy."

    ~ forum.bevelheaven.com


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