How to recognize a small or large cone crankshaft?
To recognize whether a crankshaft is a small or a large cone, the diameter of the cone must be measured. However, the difference in cone is already visible to the eye (see photo above).
The crankshaft with small cone is foreseen, by manual, for Lambretta LI LIS SX TV models.
The crankshaft with large cone is foreseen, by manual, for Lambretta DL GP models.
However, especially on elaborations, the adoption of a large cone crankshaft is also recommended on Lambretta LI LIS SX TV models.
This is because, thanks to the greater resistant section and the better conformation of the cone, the large cone crankshaft manages to avoid unpleasant breakages in the flywheel-shaft assembly.
Furthermore, the adoption of a large cone crankshaft requires the installation of the 2205 roller bearing instead of the 205 (envisaged in the small cone model) thus ensuring better resistance and distribution on the main bearings.