Oil Filter

[Ventodue]

I can just picture the scene in the crankshaft assembly shed in the great days of worker unrest, with spiteful workers pressing cranks together and shrugging their shoulders at misalignment.

And being under pressure (no pun intended) to produce enough cranks to keep the assembly lines turning (again, no pun intended) .

[LaceyDucati]

I can just picture the scene in the crankshaft assembly shed in the great days of worker unrest, with spiteful workers pressing cranks together and shrugging their shoulders at misalignment. Pressed-up cranks were always going to be a recipe for difficult assembly and high costs, along with bevel gears; no wonder Taglioni was convinced to change. I'd imagine that the fewer human operations are performed in a factory, then the more reliability will improve.

From what I have read, I believe that Riccardo work with almost every engine manufacturer in the world, possibly with the exception of Honda who have their own R+D department, although I don't know how they will survive once we are all using electric powered vehicles. The belt cam drive looks very similar to the Desmoquattro engine and I would guess that Riccardo had a hand in its design in that application.

I hate to disappoint here, but the crank truing was not the issue with the cranks the quality of components was. In fact all Ducati single cranks left the factory perfectly true, because they where ground as an assembly, quite possibly with the rod in situ. The mind boggles and it explains why many cranks refuse to true once dissembled and rebuilt, due to being originally built against untrue faces and all stressed up.

I can prove my deductions, by the facts:

1) When you trying to check an individual flywheel half between centres most times the main bearing journal does not run true to the inner centre. That is clocking on the unworn sections of the journal. Conversely unless the centre has been damaged at the nose of the wheel the diameters at that end nearly always run true. That is ignoring the oil feed nose that is always worn.

2) If you look at many cranks you will note that the taper is often not equal length all round due to the turned diameters not being concentric with the ground diameters.

I could elaborate, but I'm convinced about my assessment of the manufacturing process. The situation generally got worse as the years went on and I guess the machinery became more worn out and the financial restraints reduced the will or ability to address the issue.

I will add that, anyone thinking of simply getting there crank journals repaired by sleeving, metal spraying or hard chroming.....Think on when letting someone regrind the journal to the halves centres. If you do you most likely never get the crank to run anything like true ever again.

Regards

Nigel

[Duccout]

Very interesting! Thank you, Nigel.

[Duccout]

So that probably explains the success of the modern plain bearing cranks - the big-end journals would be ground at the same time as the shafts.

[LaceyDucati]

...and modern roller bearing cranks, where they are manufactured accurately. It should be noted that Yamaha, will sell you individual crank halves, cylinders (bored and honed) and pistons etc, that all fit together....clever chaps in Japan! I still love my old Ducatis, but I don't have any Rose coloured specs after too many years of WTF moments unpicking manufacturing and design issues

It's still a great design for the 50's/60's, just a shame quality control and manufacturing left a bit to be desired. Then again if anything it was overly optimist to manufacture what is a fairly complex design needing accurate placement of components, for what was probably a "budget" mass market price. Most opposition under took much simpler designs for the market. So the fact so many were made and survived, proves on the whole they got away with it.

For me the issues of trying to manufacture and supply parts to fit existing engines is where the trouble starts. One offs are always easy, making many parts and trying to guess what the original specs were is somewhat troubled. The detailed inspection of many original components new and used, is an eye opening experience..... Although we strive to make components a good as possible, improving on OEM components, at times you you have to accept that at worst the components will be no worse than OEM parts within original specifications. In other words, it is impossible to cover all eventualities of the design flaws and out of spec original components. That's where this forum comes in helping owners work around issues that come up from time to time as "one off fixes".

We all have the benefit of time and hindsight, that the Factory and Taglioni never had.

Regards Nigel

[Duccout]

I've often wondered about how Kawasaki, for instance, managed to produce the cranks for the Z1 series of engines that were pressed-up roller bearing assemblies and were known for being bullet-proof.

Also, I remember a letter in a classic bike mag recently written by a guy who was a development engineer for Villiers. When the Japanese bikes arrived Villiers bought a Honda and studied it in the technical department, and they came to the conclusion that Villiers was finished.

[veloduke]

I know this is a Ducati forum, but...
Kawasaki cranks, look what Allen Millyard did

https://www.youtube.com/watch?v=uW2YFNDjN_o

[Duccout]

What an amazing, skilful man he is, thanks for posting.