Crankshaft MAZZUCCHELLI AMT 162M VT For Vespa PX 125 - 150 - Round flywheels Stroke 60 Internal connecting rod 105

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

The idea behind the crankshaft at the starting point is to allow an increase in compression of the fuel mixture before it reaches the combustion zone above the piston (HPC). In the cylinder block and valve engines, the entire crankshaft circle abruptly interrupts the flow of gas inside the crankcase. Using a cylinder in which the carburetor is mounted directly on it, like the Quattrini 177ccM1XL, the true potential of an HPC crankshaft is released. This combination allows for higher engine speeds and extra power.

Mazzuchelli crankshafts are made of hard, wear-resistant materials, feature minimal machining tolerances and low bearing play. As a result, high rpm and long life are guaranteed. If your needs are not met with this type of engine, it is recommended to opt for the LPC route (e.g. bell-shaped shafts).

Result: Highly recommended in combination with engines with carburetors mounted directly on the cylinder, such as the Quattrini 177cc. It is the most convenient type of crankshaft 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 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 bearing area: 25 mm

- Beveled cone ends, thickness with M12 thread

- Bearing included

Suggestions:

- When installing a new crankshaft, it is advisable to also use new peripheral assembly 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.