High end crankshaft for Vespa fenderlight models. Highest quality for a perfect revision and a motor with maximum reliability and low vibration.
Together with the cylinder and piston, the crankshaft represents the beating heart of any internal combustion engine. It is amongst the hardest working components and the conversion of the pistons stroke to a rotary movement places the highest demands on both quality and the care taken during construction. The crankshaft should also be well balanced to reduce any unwanted vibrations and the oscillating mass kept to a minimum to support an efficient delivery of the power created by the motor. The big-end bearing rotates at the same rate as the motors RPM, receives lubrication from the petrol/two-stroke oil gas mixture and must withstand two abrupt changes in direction of the piston for each motor revolution. The crank-pin, connecting both crankshaft webs with the con rod, has to be pressed into the webs with a certain clearance to the openings in the webs. If this connection is not strong enough the crankshaft can twist and the crankshaft webs become misaligned and seize. To ensure the big end bearing receives sufficient lubrication the big end of the con rod should be provided with slots to facilitate this.
- Very good balanced
- Highest quality in materials and manufacturing
- Con-rod with generous cooling slots
- Performance variant with high-end connecting rod
The SIP crankshafts
This all-new range of performance crankshafts are produced for SIP in Italy and satisfy all of the above listed demands. We have concentrated our efforts to provide the highest quality combined with tried and tested technological features. Each crankshaft is balanced specifically to suit the stroke, con rod length and model of scooter for which it is intended.
The crankshafts available in this range can be split into two main types. The 'Premium' are equipped with a 'standard' high end con rod type, meaning that its surface finish remains unmodified. It is provided with lubrication slots and holes, for the big and small end bearings respectively.
The 'Performance' crankshaft models include a con rod of extremely high quality and they are made more enduring with an intensive polishing procedure that provides a more stable molecular structure. The smooth polished flanks of the con rod also help reduce turbulence. The polished con rods also have been optimised with a reduction in weight. They possess a gas-flowed profile and been modified around the big end to improve the bearings lubrication.
The crankshafts for the Vespa 150 GS models
For the engines of the 150 GS models we also offer crankshafts of the highest quality in different versions. We offer both the original replacement with a bronze bushing (item no. 45140500) and the more modern version with a needle bearing for the gudgeon pin (item no. 45142200). If you want to treat your GS to something more high-quality, you can use the "Performance" version with the high-quality polished connecting rod (item no. 45142300). If you want to use a PX clutch in your GS engine, you can use the crankshaft no. 45142400
Conclusion: The better replacement for the original crankshaft.
Our recommendation - SIP-TIP:
- When replacing the crankshaft always change the bearings and oil seals.
- Also very useful are the crankshaft tools # 27338000, # 21071000 and # 18119000.
Note: The VS5 crankshaft has been equipped with a connecting rod bearing instead of a connecting rod bushing. This makes the crankshaft significantly better suited for higher RPMs, allows it to run with less Oil, and reduces the risk of a seized connecting rod. SIP has now had this crankshaft remanufactured.
The GS150 crankshaft with a connecting rod bearing fits all VS2-5 models, making it the best choice for any GS3.
