MAZZUCCHELLI AMT 166M VT crankshaft for Vespa PE 200 - Round flywheels - 60 mm stroke - 25 bearing - 110 internal connecting rod

Full-circle crankshafts, also known as high primary compression (HPC) crankshafts, were originally intended for use in reed valve carbed engines. Their operating range is ideal, even with engines whose carbs are mounted directly on the cylinder itself. Extensive crankshaft development in the German/Austrian racing scene has recently enabled the 40 hp mark to be reached and even exceeded without the use of nitrous oxide. The various crankshaft design concepts all start with the crankshaft as the starting point (from Mazzuchelli).

The idea behind the crankshaft at the starting point is to allow for increased compression of the fuel mixture before it reaches the combustion zone above the piston (HPC). With cylinder-line valvetrain engines, it's impossible to avoid the fact that the entire crankshaft radius interrupts the flow of gas inside the crankcase rather abruptly. Using a cylinder with a carb mounted directly on it, like the 177cc M1XL Quattrini, unlocks the true potential of an HPC crankshaft design. This combination allows for higher engine speeds and extra power.

Mazzuchelli crankshafts are made from hard, wear-resistant materials, feature tight machining tolerances, and have very low bearing play. High rpm and long life are therefore guaranteed. If this engine doesn't meet your needs, we recommend the LPC route (bell-shaped crankshaft webs, etc.).

Result: Highly recommendable in combination with carb-mounted cylinder configurations (e.g. Quattrini 177cc) The most reasonably priced crankshaft type for most reed valved conversions.

Full circle crankshaft / 60mm stroke / 110mm connecting rod / 25mm fine taper profile crankshaft, M12 thread

Full crankshaft circle, 95mm diameter flywheel web crank part, 97.9mm diameter clutch web crank part, balanced for 12' o' clock large silver-bearing bearing, 105mm connecting rod for 125-150cc displacement, 110mm connecting rod for 200cc and up, 57-60mm stroke depending on the connecting rod fitted, oil seal area diameter -24mm, bearing area diameter -25mm, chamfered, thick profile cone ends with an M12 thread, small bearing included