Albero motore MAZZUCCHELLI AMT 162M VT Per Vespa PX 125 - 150 - Volani tondi Corsa 60 Biella int. 105

Full-circle crankshafts, also known as high primary compression (HPC) crankshafts, were originally designed for reed valve carburetor engines. However, their application is also ideal for engines with carburetors mounted directly on the cylinder itself. Recently, extensive crankshaft development in German and Austrian racing has led to engines exceeding the 40 hp mark without the use of nitrous oxide. Different crank design concepts all start with the crankshaft as the starting point.

The idea behind the starting crankshaft is to allow for increased compression of the fuel mixture before it reaches the combustion zone above the piston (HPC). In engines with a cylinder block and valve, the entire crankshaft rotation abruptly interrupts the flow of gas inside the crankcase. Using a cylinder with a carburetor mounted directly on it, like the Quattrini 177cc M1XL, unlocks the true potential of an HPC crankshaft. This combination allows for higher engine speeds and extra power.

Mazzuchelli crankshafts are made of hard, wear-resistant materials, feature tight machining tolerances, and low bearing play. This ensures high rpm and long life. If this type of engine doesn't meet your needs, we recommend opting for the LPC route (e.g., bell-shaped crankshafts).

Result: Highly recommended in combination with engines with carburetors mounted directly on the cylinder, such as the Quattrini 177cc. It is the most convenient crankshaft type for most valved-block conversions.

**Full Circle Crankshaft Specifications:**

- Type: Full circle crankshaft

- Stroke: 57-60 mm

- Connecting rod: 105-110 mm

- Crankshaft profile: 20-25 mm with cone end, M12 thread

- Flywheel diameter: 95 mm

- Clutch diameter: 97.9 mm

- Balanced for 12 o'clock or large silver-bearing

- Connecting rod length: 105 mm for 125-150 cc cylinders, 110 mm for 200 cc cylinders

- Diameter of the oil sealing area: 24 mm

- Diameter of the bearing area: 25 mm

- Chamfered cone ends, thickness with M12 thread

- Bearing included

Suggestions:

- When installing a new crankshaft, it is advisable to also use new peripheral mounting elements, such as bearings, oil seals, key, and flywheel and clutch nuts and washers.

- Cylinders with a directly mounted carburetor are ideal in combination with this type of crankshaft, such as the Quattrini M1 177cc kit. Alternatively, the use of a reed valve, such as an MMW or MBD kit, is a valid option.