Racing full cheek shaft 60 mm from Mazzucchelli for Vespa PX200
The full cheek shafts were primarily developed to improve the pre-compression ratio and thus increase the cylinder filling via the increased pressure in the crankcase. By installing the full cheek, however, the effective cross-section of the intake tract is greatly reduced. This considerably reduces the possible filling level in the upper speed range, and engines equipped with such a crankshaft usually drop sharply in performance at 7,000 rpm.
The 3 mm longer stroke allows experimentation with the timing and provides that little bit of extra displacement. Depending on whether the 3 mm is fully compensated for with base or head gaskets, the engine can be designed for more torque or speed.
DE | €
