Crankshafts
for Vespa Classic
The Crankshaft is also one of the most heavily stressed engine components on a classic Vespa. It rotates thousands of times per minute and the performance of an Engine depends on its quality. Minimal manufacturing tolerances, high speed stability, low bearing play and maximum durability of the Shaft are the basic requirements for optimum engine tuning. Crankshafts in Engines that have already clocked up a few kilometres or have more power often have worn Bearing and shaft seal seats or worn connecting rod bearings. In such cases, it is advisable to replace the Crankshaft during an engine overhaul.
In the field under "Classic Vespa" you can now select your "Vehicle type" to see all suitable Crankshafts.
The different Vespa model series
With Vespa scooters, we basically differentiate between the models according to their frame widths:
Smallframe
- Vespa 50-125/PV/ET3/PK/XL
Wideframe
- Vespa 98/125/150/GS `-56-
- Motovespa
Largeframe
- Vespa 160 GS/180 SS
- Vespa 125/150/Rally `57-
- Vespa PX/T5/Cosa
- LML 125-200 4T
The different crankshaft types for classic Vespa
We divide the Crankshafts for classic Vespa scooters into the following groups.
Standard crankshaft
Standard crankshafts are replicas of the originals. Improvements have also been made to some models, e.g. a Gudgeon Pin Bearing for a lower frictional torque instead of a bronze bush or a polished forged connecting rod. We have also replaced the original conical clutch stub on some Shafts with that of the late Vespa PX Models. The transition to Racing Crankshafts is therefore seamless.
Racing crankshafts
Racing Crankshafts are basically all crankshafts that deviate from the pure standard specifications. So:
different crankcase shape
more stroke
longer or higher quality Conrod
Clutch/pole wheel stub is not intended for the original parts
optimised intake geometry through shape and cut-out
The range of smallframes and largeframes is so large that we also offer them in Disc Valves and Diaphragm shafts and diaphragm shafts.
Special racing crankshafts
Special crankshafts require special Crankcases. They are not suitable for the original crankcases, e.g. the SIP BFA crankcases for largeframes or QUATTRINI or BFA crankcases for smallframes.
Our top brands for Crankshafts for classic Vespa Models
The most popular crankshaft manufacturers for classic Vespa models are
MAZZUCCHELLI: Good and favourable standard and Racing Crankshaft. Made in Italy.
SIP SPARE PARTS: Special small series for Vespa classic cars in top quality.
SIP PERFORMANCE: Developed by the brightest minds at SIP and produced in a high-tech tuning centre in Italy.
PIAGGIO: Large selection of classic Vespa Crankshafts.
POLINI: Back to the roots! Active again in the crankshaft market for Vespas for several years.
PINASCO: Beautiful Shafts for classic Vespas.
DRT: High-quality Crankshafts from the Italian forge.
QUATTRINI: Perfect for high-performance tuning.
Technology tips
If you want to delve even deeper into Crankshaft technology, we recommend our Technology blogs.
Customers ask - SIP answers
"Do I compensate for the extra stroke of a Long Stroke Crankshaft with a head or foot seal?"
In principle, the extra stroke should be compensated for with a head gasket (0.5 x difference to the original stroke (e.g.: 60 mm-57 mm = 3 mm x 0.5 = 1.5 mm gasket)). With the head gasket, the timing increases only slightly and the characteristics of the Cylinder are retained. If a base gasket is used, the timing increases relatively sharply. However, the advance flow decreases at the same time. This results in an unfavourable ratio. This only makes sense if the exhaust is additionally machined.
