for Vespa T5
disc valve
stroke 52.0mm
conrod 105.0mm
Sport – con rod
pin 16mm
valve timing: 111??/-9?? post TDC
fine balanced

Grade AA – first-class repair and for tuned engines
Product description
Together with the cylinder and piston, thecrankshaft 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.The crankshafts:
This all-new range of performance crankshafts are produced forin 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.Conclusion: The ideal crankshaft for mild, reliable tuning projects. It can enhance a wide range of uses, from a slightly tuned standard set up through to a Malossi sport cylinder combined with a big-box exhaust with a motorway friendly 20 PS.
– TIP: While replacing the crankshaft do not forget to also renew its bearings and oil seals! The extra stroke is compensated for with a 1.5mm thick cylinder head gasket, or the use of a 60mm stroke compatible cylinder type (e.g. #31163510, #15060000). The port timings listed above are determined while facing the clutch side of the crankshaft. For example, ‘138??/6?? past TDC’ means the inlet port is opened 6?? after the crank-pin has passed BDC and is then opened for 132??.
OEM numbers (for comparisons): (PIAGGIO)
EAN Number:
4260277182489