Desmo-why’s….ENG VERS

28 Apr 2015 | Author: | Comments Off on Desmo-why’s….ENG VERS

Desmo-why’s….ENG VERS

di Giorgio Mulliri

Pubblicato il 29 agosto 2012


I have always tried to follow the evolution of Ducati motoGP with focus on news not of public domain on the web or in the press, most often predicting successive development steps based on problems encountered. I am not saying that what Filippo Preziosi said during testing in Jerez, “Manziana, you’re the only one to have understood us”, authorises me to claim expertise, but rather that I am a passionate and keen observer. I am not in a position to judge the work created by an engineer considered by many to be the genius of motoGP a few years ago, a reputation earned himself by his original concept of motorcycle different to the general standards of the time, and who, after the interview with Furusawa, is now considered in the collective imagination of many to be like a child in kindergarten that hangs from the lips of the teacher.

I personally do not share this view, I have always reasoned along a technical line to explain Ducati’s gap, and also suggest that according to me, development delays of the gp12 were mainly due to administrative issues (change of ownership)

rather than lack of ideas on behalf of the project responsible, Filippo Preziosi.

Proof of this is the fact that during the 2011 season the following versions took to track (in this order): gp 11 – November 2010;

a gp12 litre bike made its track debut in April 2012 in Jerez

with different design concept to the gp11, such as Yamaha/Honda type suspension, to subsequently use some of the gp12’s prototype thus making the ex-gp12 the 2011 championship’s bike. To the same chassis the 800cc engine was mounted and was labelled gp11.1

to then become the gp11.2

when carbonfibre was abandoned for the semichassis in favour of aluminium for the Aragon debut, and subsequently in September during testing in Jerez the perimetral framed 2012 litre bike made its debut and then in November at Valencia together with all the other new litre bikes (the real gp12 made its track debut only in Sepang 2012), and the gpzero, selected by Barbera and Abraham due to the frame’s superior stiffness with respect to Rossi’s choice

(three different frames were tested in Valencia), which took part in the November 2011 tests with the engine boosted to 1000cc practically ready for the 2012 season.

Question: after all the efforts profused during the 2011 season, with new engine fusions and new frames, is it possible and credible that Ducati, for 2012, only made one new swingarm, a few new traction control software programs and some internal engine modifications to obtain a smoother power delivery?

This is fact. My hypothesis as to why, I highlighted in my article.

Via several articles I attempted to explain where Ducati was and hypothesised where they were heading to with the successive project changes in order to adapt to Honda and Yamaha competition, the survivors of the general economic crisis after Suzuki and Kawasaki abdicated.

It’s not easy to try to explain specific steps or choices made by Filippo Preziosi. Logic suggests obliged milestones undertaken by a person perfectly aware of the in-house material at their disposal and the path to follow in order to reach an optimal solution for a competitive bike.

Starting with Preziosi’s declaration during the Madonna di Campiglio presentation of the gp12, which in reality was not ready yet: “what we are about to face is very challenging. From the concept of a motorcycle to the first race usually takes two years, our will instead be a path in hyper-drive with which we are confident to succeed. It’s a bold choice but not an impossible one and Ducati have already shown we can do it.”

Nakamoto, the HRC boss, is of the opinion that it takes three years, in order to obtain an optimally competitive bike, but they were starting from an already winning bike, which stepped up in engine capacity while maintaining and improving all concepts implemented.

And in order to reach that result, obviously, they adapted every component step by step in order to obtain an assembly that behaved in a specific way. We refer to engine design together with all internal organs and their respective collocation, and include the frame designed together with the engine in terms of different stiffness parameters in order to satisfy the response to rider’s sensations. All this has been established over years of competition by Honda and Yamaha in order to achieve and optimal situation relative to any specific moment.

We refer to winning bikes, with years of experience both in frame and engine development.

What I’ll try to explain here may seem strange and banal but looking attentively at these motorcycles, a geometrical “constant” relative to the engine collocation within the frame, appears.

The words expressed by Furusawa during his meeting with Preziosi, when he referred to his design concept of a “magic” triangle which was to be established between ground contact points and the centre of gravity, CoG, of the bike, which was to lie within specific parameters, induced me to better understand this concept.

Browsing through photos of Honda and Yamaha, even if I couldn’t know where the CoG lay, allowed me to note the previously mentioned constant. In both bikes, Honda and Yamaha, it is apparent that the front sprocket and consequently the secondary drive shaft is positioned almost exactly in the middle of the bike’s wheelbase, evidently indicating that if the two Japanese manufacturers had converged to this position, this constant was a fixed sign of a good balance of the engine within the frame.

Have I discovered hot water? No, I just noted a common detail.

Hrc rcv 213 sepang test

Ducati no, Ducati has a different aspect, at least on the gp12.

It is known that the Ducati is too loaded on the rear wheel. Uccio, in an interview to Mediaset 2 expressed Rossi’s perception of the gp12 as the weight distribution feeling similar to a chopper, even though other bikes had this type of distribution but we do not know the real weight distribution since the rider’s position and weight is an integrated part of the final complex balance of the bike. (Problems relating to the frame’s contribution to the ride characteristics are another important issue in terms of stiffness/flexibility which play an important role but the bike must first have a good equilibrium in terms of weight distribution).

These photos show this constant.

And this photo refers to the actual gp12.

Can Preziosi have got this bike seriously wrong? No, I do not think so, his choices according to my reasoning foresaw an adaptation to the existing material prior to investing in a new engine and frames.

This is confirmed also by a recent interview to Burgess who claimed that a frame was made to fit around an existing engine, the 4 cyl 90 L-configuration rotated backwards also in order to allow positioning of the fuel tank below the seat like for the Japanese bikes. This was not the case until the gp12 and gpzero which had the engine positioned farther forward weight-wise with respect to the current one.

The gp10 and gp11 had the front cylinders far enough forward to require the radiators to incorporate an adequate window to accommodate the heads, and the bike apparently respected the constant previously discussed, referring to the front sprocket lying midway or almost, along the wheelbase. In order to centre the weight it can be required to work on the wheelbase by lengthening the swingarm, but lengthening the wheelbase can have a negative effect on the manoeuvrability, and this effect Ducati has always suffered due to the volume occupied by the desmo engine which has forced these choices.

Preziosi worked with the “old” engine also because, as Burgess points out, the frame was designed around that engine and consequently, it has been attempted to adapt it to the various “standard” parameters of a competition motorbike.

The only fixed point which was respected was the front sprocket position, which obviously has to lie at a certain height and within a certain distance from the swingarm pivot. These compulsory parameters ended up being restrictive as Burgess pointed out too.

GPzero VS GP12 posicion crankshaft

What problems did Burgess identify? The impossibility to move the engine in order to alter balance, due to restrictions in front sprocket position with respect to swingarm pivot. The same situation occurred with the carbonfibre chassis bike which required a differently dimensioned chassis every time the bike geometry was to be altered when trying different settings, or lengthening the swingarm.

Until the gp11 the swingarm pivot passed through the engine case, another fixed point, which could only be modified by using different size concentric sleeves or by recasting the engine cases with the new dimensions.

I think Preziosi required real data before embarking on a new project based on experience obtained on the current gp12. In other words, prior to making a totally new engine in terms of shape and position, he had to have the solutions. Once the problems have been identified a new project can be made starting from one and not from zero, but with parameters obtained by the previous experience.

In the tests after the Mugello race, the updates included a new design for the underseat tank and the repositioning of a few components (electronic control units) forwards on the bike, in order to modify weight distribution thus confirming it to be too far backwards.

Ducati 350 S Desmo

When weight distribution repositioning is modest (such as for Yamaha and for Stoner’s Ducati in Aragon 2010), lengthening of the swingarm and displacement rearwards of the forks by using different yokes is used, respecting the original wheelbase. This refers to millimetre changes which took the 2009 Yamaha to an optimal balance which allowed the rear tyre to be warmed better, and the results are known.

The relative article:

I think this was the path which was interrupted during development, by the new ownership which

wanted to know what/how/when/how much will it cost. We are talking millions of euro, a careful analysis by Audi on what can be done internally and what should be outsourced, we are talking of comparing experiences and reinterpreting regulations while waiting for their approval. Why build a new engine if it cannot be used in 2013 unless it is again, adapted? (Electronic control units and 15,500 rpm compulsory and fixing of engine bore and stroke?)

We are talking about electronics and double injectors, where Marelli contributes, but where the Germans collaborate strongly with Bosch, surely interested in the Italian technology. Will Marelli agree? It is not all hypothesis, there are various and complex considerations before considering Preziosi finished.

The meeting between Preziosi and Furusawa I interpret as a request to compare ideas and not on how to make a motorbike. The challenge for Preziosi is to leave the engine as an L-90 and to make it a winning bike; this is the challenge and Furusawa refused it by slamming Preziosi’s door.

To change the L-90 into a narrow V like Honda and the old Suzuki in order to make it more positionable within a frame would be like admitting that Preziosi’s path was wrong.

desmo sedici capirossi 2006

To switch from desmo distribution to pneumatic valves as suggested by Pernat and Lucchinelli in 2003 claiming it to be outdated. What sense does that make, if the desmo distribution forced the greatest Japanese manufacturers to change their spring distribution in favour of pneumatic valves in order to contrast the power of the desmo from Bologna? It would also take years of development of a new technology in order to make it competitive.

I remember Honda was the last of the Japanese manufacturers to switch from springs to pneumatic valves and not without problems. Engines also exploded and the HRC technicians were forced to wonder along the track picking up pieces of pistons and other diabolical engine parts made in japan from Hayden’s bike.

Even Kawasaki went to Mecacrome, for their pneumatic valve head. Mecacrome was the company that followed Renault’s engine development (who invented the pneumatic valve scheme in F1) after Renault officially left competition before returning several years later. Do you remember Qatar of a few years ago, with Hopkins kicking his smoking Suzuki leaned against a wall?

The challenge is to develop a concept which distinguishes from others. Currently a Ducati CANNOT NOT BE desmodromic and its battlehorse is its L-90 engine.

Will Ducati manage to maintain this identity in the future? Rossi’s words with regards to Ducati’s future imply that many things will change within the racing department. Also Del Torchio’s words that did not support Preziosi’s action and defined it as isolated and distant to company decision, suggest dark clouds on the horizon for the racing department.

I strongly hope they continue to have confidence in Preziosi. The real gp12 has not been finished yet and the various development steps that were meant to be taken to Laguna Seca unfortunately have not been seen. What will Dovizioso test? For sure the old gp12 and I think the new one with a new engine with a new form including the double injectors connected to the traction control, like the competition, and of course a new frame.

The whole thing after having established what does not work on the current gp12 before delving into a multimillion investment. When? Sepang test 2013 if all goes along to plan. Making a new engine is not simple, it requires designing, moulds, testing tens of engines before giving the green light and obviously it must be an engine that respects that “karma” of equilibrium between components that Ducati has searched entering that road with no light.

When can you improve a bike? When you see the defects of the previous one. Does a Ducati with an aluminium twin spar frame and dedicated engine, exist? No, it does not, and this is the base.

If I want to hava a bike better than the previous one I have to undertake the current one and implement corrective action. Have the others already crossed this phase? Yes, since years. Ducati?

Ducati had no experience with a perimetral frame.


This is the starting point. All the rest that has been done before (carbonfibre) has been put aside and is not useful if a new and unknown concept is to be used (perimetral aluminium).

I’d like to thank William Adam for the translation

Ducati 350 S Desmo
Ducati 350 S Desmo
Ducati 350 S Desmo
Ducati 350 S Desmo

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