The flowed crankshafts belong to the Low Primary Compression (LPC) crankshaft type which originally leave the factory as MAZZUCHELLI or TAMENI full circle crankshafts. The SERIE PRO range of crankshafts are produced by the German tuners WORB5.
These flowed crankshafts are specially machined to optimise gas flow in the pre-combustion area of the crankcase. The crankwebs have been modified to enable the fuel mixture free flow, unhindered from the turbulence created by the crankshaft. This design also allows a higher volume of fuel mixture to enter the crankcase and so enable a higher compression of gases above the piston in the combustion area. This combination facilitates a wider power band and consequently higher maximum power. Flowed crankshafts are only suitable for use in reed valve motors. The original Vespa disc valve mechanism provided by the clutch side crank web is no longer possible with this heavily altered crankshaft.
Conclusion: Perfect for reed valve motors. Larger, gas flowed ports and inlets are finally possible!
Flowed crankshaft / stroke 45mm / connecting rod 105mm /M12
Flowed crankshaft with Ø 95mm crankweb (flywheel side), Ø 94mm crankweb (disc valve side), 105mm connecting rod, lower connecting rod bearing = sillver bearing, oil seal housing 24mm, bearing housing 25mm, stump cone with M12 thread, incl. piston rod bearing
SIP-TIP: New bearings, oil seals and keys are a must. Same goes for sealing kit, clutch-, and flywheel nuts. You’ll also need a POLINI, MALOSSI or MRP reed valve manifold.