Racing shafts are a simple and effective tuning step for any rotary valve engine: they enable higher engine speeds, making the engine more lively and agile. The high-quality racing shafts from the Italian company MAZZUCCHELLI impress with their low manufacturing tolerances and minimal bearing play. This enables high speed stability and a long service life.
In contrast to the original crankshaft, a racing shaft has a significantly longer intake time, which increases the degree of filling. The crank webs are streamlined and polished to reduce turbulence and stalling. A likewise polished cutter connecting rod and a lower connecting rod bearing as a silver bearing meet high demands. All crankshafts are supplied with upper connecting rod bearings.
If you want to convert to electronic ignition, you should go straight for the 20/20 mm racing shaft. The thicker, more stable cone is also recommended in combination with a racing cylinder. For high-revving engines with powerful cylinders or very light fan wheels, an ETS shaft should be fitted to avoid the risk of the crankshaft stub breaking off. In V50/PV/ET3/PK engine housings, a conversion bearing and the appropriate shaft seal are required for this.
The RACE version has a reinforced connecting rod. Additional lubrication holes in the upper connecting rod eye (only on 125cc models) and lubrication slots in the lower connecting rod eye improve lubrication, increase stability and allow higher engine speeds.
Conclusion: Not only useful in combination with a tuning cylinder - an increase in performance can be achieved even with original cylinders. MAZZUCCHELLI stands for high quality, long service life and durability.
Racing crankshaft / stroke 51mm / connecting rod 97mm / 24/25mm, M12
Racing crankshaft with Ø 82mm crankweb (flywheel side), Ø 87mm crankweb (rotary valve side), 97mm connecting rod with 2 additional lubrication bores, oil seal housing 24mm, bearing housing 25mm, stump cone with M12mm thread, incl. connecting rod bearing
SIP-TIP: New bearings, oil seals and keys are a must. Same goes for sealing kit, clutch-, and flywheel nuts. When using a V50/PK/PV/ET3 crankcase, you?ll need a conversion bearing oil seal. It also makes sense to use the crankshaft tools # 27338000, # 21071000 and # 18119000. Ideal for POLINI, MALOSSI, DR and PINASCO racing cylinders with rotary valve.
