Was nattering away with my mates in the boozer the other week about bikes as usual. I was asked, "why do ducati's use belts and not chains like most others"? I don't know. My mate has an aprilia twin and i think those are chains as are the honda and suzuki twins? Anyone know? Could ducati not use chains for some reason? Is it because of the valve set up? Anyone enlighten me please?
The first production Ducati to use belts was the Pantah, introduced in 1979. The previous bevel models had become too expensive to manufacture, build and shim. The chain drive 500GTV vertical twin of 1975-79 was a failure in showroom sales. Belts were very cheap, so it was a simple solution. Non-desmo engines are harder on their cam drive systems, because of the resistance of the valve springs, and if they used belts would need larger pulleys - but this is an issue only Ducatis avoid. It was the brilliance of Fabio Taglioni to think of introducing belts which are cheap to buy, compact, cheap to fit in the factory, silent, don't need lubricating, and work well provided the valve gear is desmo. Every twin Ducati introduced from 1979 up to the 1198 has stuck with belts, with some detailed variations. Until the 2012 Panigale, which of course uses chains much like every other manufacturer.
Same reason they are used in car engines, cheap to fit and quiet (they don't rattle like a chain). Also, chain-driven cams need regular oil changes whereas belt-driven are less fussy. In short cheaper and quieter for manufacturers but more expensive for customers and catastrophic for customers if they break but they are usually well out of warranty by then anyway so the owner picks up the bill. Mechanic friend of mine reckons that a belt is more likely to fail at tick-over than high revs.
Yeah,i had a belt fail on me once. All the people in Tescos got a right eyeful of my skiddy drawers!!!:wink:
Pete, you know every bloody thing!!!! Thanks for posting as I have always wondered but never really wanted to ask in fear of being perceived as a window licker. However I have acquired window licker status on this fine forum due to my piss poor spelling and grammar. I have come to terms with it.
Belts are ok, chains don't need to be noisy (think bentley Jaguar and Rolls-Royce) belts do ensure a regular parts return, as well as more workshop time (more labour) most cars now run chains, as belts have gone out of fashion, and I believe pretty much all bikes. Not sure about the two oddballs, the pan European and gold wing - both used to have belts, not sure if they still do.
Only two modern Ducati's don't use belts - Desmo (gear driven) and Panigale (chain driven) given the Panigale has a next gen engine I suspect in the future they'll be a shift that way
The reasons for ceasing to use bevels and shafts for driving cams were perfectly valid at the time, in the 1970s. But times have changed, and Ducatis are able to command premium prices now. They should have developed a new bevel system for the Panigale, rather than the ordinary and commonplace chains. With modern materials and manufacturing methods, and screw adjustment for lash instead of shims, bevels would be feasible. More important, bevels would be a 'Unique Selling Proposition' attracting publicity and customers. Well that's what I think.
The Panigale uses a mix of chains and gears to drive the cams, a bit like Suzuki's TL1000 motor. Worth noting that a lot of Honda's have used gear driven cams, eg:RC30, RC40, RC45, RC51, lots of the 400c bikes and VFR's up to the v-tec model.
Oh dear. Being called a know-it-all is usually considered an insult, but on this occasion I choose to take it as a compliment. So thank you very much, Troy.
According to various books about this period (by Alan Cathcart, Mick Walker, etc) the GP 500 first raced in 1971 and on & off up to 1974 was made in several different versions for experimental purposes, with: bevels or belts, 2-valve or 4-valve, valve springs or desmo, points ignition or electronic, carbs or fuel injection, and different frames. By 1973 it had 4-valves, dohc, desmo, belts, and the rear head reversed - much like the later 851.
How can they say they used belts because they are quieter!!!! At tick over on the 1198 with its dry clutch (open cover) and a full termi system they could have installed belts made from any material they wanted, I doubt you would be able to hear them!!! Belts were used to ensure regular service bookings. Smart business sense.
Thanks all, I am enlightened! Not sure about the chain and noise issue though as jap bikes sound smooth and quiet to me!
Huge progress has no been made over 30 years but in the early 80s the rattly camchain was a common sound. One of the main reasons I bought my first Pantah in 85 was because it didn't have a camchain. I'd had enough of elastic band Honda ones.
Also in the 70s automatic cam chain tensioners had not been perfected. Several models from various manufacturers would suffer from tensioner failure, closely followed by severe chain wear.
