Ducati Desmodromic rockers...
What are they?...
The rockers in the desmodromic valve system fit between the cam and the valve, simply put : they are the levers that open and close the valve.
The gap bewteen the rocker and cam is the valve clearance, this is a very important measurement.
What is the problem then?...
The rockers have a hard chrome plating on the surface where the cam rolls against it.
This chrome plating can suffer from flaking and brake up. see below:
Which models are affected?...
Some years / models are affected more than others, it's known that Ducati changed their subcontractor of these parts in 1996, and the 4valve models (748 / 916 / 996) suffered from worn rockers more than usual up until 2001 when they changed supplier again.
Taken From Ducati's Technical website pages...
We'd like to take advantage of the accessibility of the Internet to let you know that for Model Year 2001 (MY 2001) we have fitted new generation engine valve control rocker arms as standard parts in all our motorbikes. The new MY2001 rocker arms are entirely compatible with all earlier versions, starting from the first version of the Ducati 851 model, and are now the only ones supplied.
With the introduction of these modified rocker arms, we believe that we have the answer to every possible problem relating to rapid wear of the engine valve control faces. We would however like to remind you of the possible causes of early rocker arm wear:
Not carrying out checks, which include adjusting the engine valve clearance, as regularly as indicated in the routine maintenance schedule contained in the Ducati warranty booklet.
- Engine valve clearance not adjusted to comply with the standards laid out in the Ducati workshop manual.
- Use of an engine lubricant that does not conform to specifications indicated in the Ducati use and maintenance manual.
Since the problem does not affect the users' safety and would not indirectly damage other engine parts, Ducati will not carry out a preventative recall campaign. As always, Ducati is available to answer fully any questions you may have.
DUCATI Motor Holding spa Technical Assistance Service
What causes rocker wear?...
The internet is full of theories on this topic, certainly the everyone has an opinion so I won't dwell on it. whatever the reason, it really doesn't matter.
Although some of the problem can be blamed on the poor chrome plating, the new 2001 rockers weren't entirely the end of the problems, there are several other factors that are to blame, these you can do something about...
So What can you do...?
Rocker wear is caused by several factors and there are a few things to keep in mind that will help your motor, not just the rockers, stay in top condition:
- Valve clearances MUST be adjusted correctly
- Too tight is fatal but too loose can also be very bad.
- To check the clearances properly takes some practice and experience, its a tricky job, that, unfortunaltly we know not all dealers do correctly (or even at all). It is vital but often overlooked by workshops who are just not used to working on Ducati's. A sad fact but true.
- Let your bike 'warm up'
- Let your bike sit at tickover for a couple of minutes before you ride off, this gives the oil pump chance to get oil round the motor. The oil works best a the normal running temperature and all the components of the motor expand at different rates, but they all work together when hot. Ideally, let the motor run for 90-120 seconds before riding off, then keep the revs in the lower third of the range until the temp gauge has moved up to normal.
- Use good quality oil - We use Shell fully synthetic.
These things are simply common sense, when we strip our race motors they are nearly always in better condition than the road motors we see, this is not only because they are hand build and dont do many miles (but they do spend most of the time at the red line!) but because they get new oil regularly and always get carefully warmed up each time they are used.
So why all the fuss...
Ducati does suffer from 'pub talk' experts. Problems such as these are often blown way out of proportion, if Suzuki have a batch of bikes that brake cam chains/tensioners (GSXR600, 98-99) or Honda rectifiers and ECU's fail (CBR900. CBR600 etc) then the public reation is "Well they are cheap" or "but the rest of it is ok" but when a Ducati indicator bulb blows, hear the crys of "Italian electrics eh!?! I'd never have one!" sound familar?? - Look after your Ducati and it will look after you. (but if not, we will !)
Wilf
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