Here we have Malossi’s Full Circle crankshaft, or high primary compression (HPC) crankshaft as our continental friends like to call them, for the Vespa 200. This crank has a 60mm stroke, which is 3mm longer than a standard crank, and the webs are full circle, which makes this crank only suitable for use with a motor modified to reed valve induction.
As these cranks are designed for motors producing allot more power than standard Malossi Vespa Cranks are made from aeronautical quality reinforced steel and are founded in a vacuum. It is a material highly resistant to scratches and guaranteed by the certifications required in Malossi’s strict handbook. The “viper head” piston rod’s shape is designed to limit weight to a minimum whilst guaranteeing the required rigidity. Malossi have also revised the threads used on both sides of the crank to a finer pitch, the clutch side no longer has the cut out for the tab washer, to give the crank more strength and is supplied new Special crank nuts so higher torque setting can be used on both the flywheel and clutch.
The full circle crank really comes into its own when used along with Malossi’s reed valve crankcases VM577230, on which Malossi have moved the inlet port forward so the inlet in more over the open area in front of the crankshaft, rather than the inlet port being directly above crank as on standard and Pinasco crankcases.