Crankshaft -MAZZUCCHELLI bell-shaped shaft (for diaphragm intake) - 60mm stroke, connecting rod 110mm, Ø16mm, incl. conversion bearing for Ø15mm piston pin and 5mm spacer for cylinder base - Vespa PX125-150

Mazzucchelli bell shaft 60/110 for Vespa PX125-150

Made by the traditional manufacturer Mazzucchelli from Italy: MAZZUCCHELLI bell crankshaft (for diaphragm intake) - 60 mm stroke, connecting rod 110 mm, Ø16mm
Incl. conversion bearing for Ø15mm piston pin and 5 mm spacer for cylinder base - Vespa PX125-150

A new type of shaft has been designed to provide the maximum possible cross-section. The so-called bell shaft (or mushroom shaft) offers:

• maximum flow cross-section
• maximum stability
• perfect balancing
• Connecting rod length 110 mm (standard 105 mm) - 5 mm spacer included for compensation
• Ø16 mm piston pin boss - conversion bearing for Ø15 mm pin included

CONVERSION SHAFTPX200 => PX125/150
The shaft shown here is based on the version for the PX200. It therefore has a 5 mm longer connecting rod than is usual for 125-150 cc engines. The piston pin boss is also 1 mm larger with a diameter of Ø16 mm (standard 125-150 cc = Ø15 mm). The longer connecting rod reduces the forces on the piston skirt due to the better connecting rod ratio. In addition, the pre-compression is reduced. Both of these benefits smooth running and power output.

MODIFICATIONS
So that the crankshaft can be used in 125-150 cc engines (PX80 also fits with the corresponding cylinder in the 125-150 cc class), a conversion bearing for the piston pin and a 5 mm thick base spacer without cut-outs for the transfer ports are included. This crankshaft is therefore intended for ambitious mechanics who want to massively increase the performance of their engine and who enjoy modifications (e.g. the overflow cut-outs in the spacer must be adapted to the respective cylinder).

Despite its unusual shape for Vespa riders, the shaft has no loss of stability compared to a conventionally shaped shaft. Anyone who has ever looked at the crankshaft of a Ducati will probably realize that this design is not only well thought out, but also makes sense for a high-performance engine.

In combination with the increased stroke of 3 mm, the result is a crankshaft that is perfectly suited to the demands of an extremely powerful PX engine.

With a large diaphragm intake manifold and a carburetor from 28 mm to 38 mm, an engine with the right cylinder/exhaust selection can easily shovel over 35 hp to the rear wheel.

Of course, you can also build beautiful touring engines with such a bell shaft. The advantage here lies in the wide speed range and the better torque curve even at low revs due to the longer stroke and larger displacement. The very low-vibration running is just the icing on the cake ...