High-end Crankshaft for Vespa Largeframe Models. More stroke and top quality for high-torque everyday engines.
The Crankshaft, together with the Cylinder, forms the heart of every Engine. It is one of the most heavily stressed parts. The conversion from stroke to rotary motion places the highest demands on quality and workmanship.
- Particularly smooth running
- Very high-quality materials and workmanship
- Available with polished forged connecting rod
The Crankshaft line from SIP is manufactured in Italy and meets the highest demands placed on crankshafts. Particular attention has been paid to the highest quality and sophisticated design features. The balancing of each Crankshaft is adapted to the stroke, connecting rod length and scooter model.
The shafts are available in two versions:
The "Premium" Models are supplied with a high-quality Conrod in standard design, i.e. with an untreated surface. The Conrod is equipped with cooling slots and holes for the bearings.
The "Performance" Shafts are fitted with an extremely high-quality polished Conrod. Polishing refines the surface. This means that it becomes denser and has a more stable structure, which makes the Conrod more resistant. The polished surface also ensures less turbulence. The polished Conrods are further weight-optimized. Their lateral contour is more aerodynamically shaped and they have been reworked in the area of the lower bearing for even better cooling of the connecting rod bearing.
Disc Valve timing
125°/-5°: with intake timing extended by approx. 20°. The longer timing is very suitable for "sport" tuning. At the same time, the times remain within a frame that is still very suitable for everyday use. Engine performance is not lost in the lower rev range and can be easily tuned. The "sprayback" from the crankcase remains at a low level. The contour of the control cheek is designed to allow the gas to flow in as smoothly as possible. In addition, this type of cheek design allows particularly effective balancing of the Crankshaft and therefore particularly smooth engine running.
The stated timing values have been determined with a view to the clutch side. For example, "138°/6° after TDC" means that the intake opening starts 6° after the Crankpin and is then open for 132°.
Note: The rotary vane cheek of the SIP Crankshaft has a particularly precise fit for smooth engine running. In conjunction with aftermarket casings or faulty rotary slide surfaces in the casing, contact between the Crankshaft and the casing may occur. Please check the dimensional accuracy before installation.
Conclusion: The ideal Crankshaft for mild, reliable tuning from the improved original engine to the Malossi Sport with box exhaust and 20 hp suitable for touring.
The best setup - our SIP-TIP:
