Notes, comments, choices and challenges of Engineer Dell'Acqua
I have to say that the task hasn't been easy at all.
I never had the possibility to see or test the Innocenti prototype. The only images I've seen are those on Vittorio Tessera's book, where heavy alterations on the original frame to allow the insertion of the bulky engine can easily be noticed.
I can assure you that the task to fill less volume than how much Innocenti already did and also to install in the few free spaces bigger carburetors making no alterations to the geometry and to the original position of the tank and carrier, have been really complicated.
This is not all.
We wanted to keep the original engine philosophy to have continuity with the work done 40 years ago and also to confirm that the path followed by the factory, was valid crankshaft.
The drive shaft, for example, has been mounted inside the case.
We realized it followed the guide lines of the last Innocenti's prototype of which we have been able to have not detailed drawings.
Compared to that one, our drive shaft is bigger, more robust and it delivers a better engine torque. Some details added have been very effective, so that even I was surprised by the robustness and the performances showed until now.
We also have analyzed well, the possibility to use a different crankshaft, a one piece drive shaft press assembled , but that would bring the adverse drawback of having a case open in two and vertically dissected for obvious reasons, that would make practically impossible the realization of the engine supports. What is worse is that that choice would have reduced its torsion rigidity and to make up for it we would have to put lots of fixed screws between the two rams so that we couldn't place the carburetors in the right position inside the hoods.
That's not all. That choice would had a drastic and negative influence on the geometry of the engine clamps on the frame penalizing the project that would have failed since all the elements were not able to be placed inside the frame unless complicated alterations that no Lambretta rider, us in first place, is willing to accept. As you can understand, all the choices made are a compromise between the different needs we had to face.
Even cylinders come from the Innocenti prototypes, with suction controlled by the piston.
The four transfer ports are not as big as I would have liked, but the crankcase in between is so little that the result can be considered a miracle. We also thought to use the reed valve, but the idea has been rejected only because the increment in the volume would have placed carburetors in a position interfering both with hoods and carrier.
There have been more difficulties and problems to deal with but I don't want to bore you so I won't list them. It's enough for you to know that this project took up my free time until December 2006.
My wife, in some ways, resigned herself, and now she's really proud.
I dedicate this work to my one year old son Gabriele. May he be "lambrettistically" proud of his father one day.
I wanted to synthesize in these few lines, the guiding lines and difficulties found on the road to what I think is the best Lambretta product of the last 30 years.
Sincerely,
Gianfranco Dell’Acqua
CONCLUSIONS
Dear Franco, Engineer Franco, even if you don't like to be called that, it's been and still is a pleasure working with you, the results arrived, neither of us had doubt about that.