Racing crankshaft Sport by Mazzucchelli with large taper for the Vespa PK 50 XL and XL2.
Standard Crankshaft vs Racing Crankshaft
Timing
A racing crankshaft is distinguished from a standard crankshaft by a modified crankshaft cheek, known as the "rotary valve". The opening of the rotary valve is larger, allowing a longer period for the mixture to flow through the crankshaft chamber via the rotary valve sealing surface during one crankshaft revolution.
A racing crankshaft ensures efficient fuel supply even at high speeds and provides linear power delivery without the engine starving of fuel at higher revs. The inlet timing can thus be easily and non-destructively extended without enlarging the rotary valve sealing surface of the engine housing through milling. Especially engines with larger displacement and sporty channel design require optimized mixture supply, especially in the highest gear under full load at a certain RPM.
Connecting Rod
A racing crankshaft often has a different connecting rod installed. This connecting rod is a polished knife rod, which ensures minimal resistance in the crankshaft chamber at high speeds and reduces mixture turbulence.
Technical Specifications
- Stroke: 43mm
- Type: Racing crankshaft
- Taper: Large taper 20/20 mm
- Connecting Rod: Polished knife rod
Mazzucchelli code: AMT028
