Polini Crankshaft Evolution 2010 conrod=85mm / piston pin=12mm Yamaha Aerox

How to change a crankshaft?

The crankshaft is one of the main components of the engine and is responsible for the smooth operation of motorcycle, scooter and moped, whether with two-stroke or four-stroke engine. The longevity of the engine depends not only on the proper condition of the crankshaft, but also on the fact that it is properly mounted.

For a correct installation of the crankshaft, we recommend our tutorial: Crankshaft disassembly and assembly.

How can I tell if my crankshaft is Damaged?

A broken crankshaft causes metallic noises, unusual vibrations, leaking oil seals and drastically reduces the performance of the two-wheeler. In any case, the vehicle must be stopped immediately to prevent the damage from getting worse.

Please note that whenever the crankshaft is changed and serviced, you'll have to install new crankshaft bearings.

Tuning Level: High End racing

We categorize our products into different performance levels  Original, Sport, Racing and High End , so that our customers can choose the right parts for their setup. It is really important to combine parts that belong to the same tuning level, this is especially true for cylinders, crankshafts and exhausts.

High End Racing products are exclusively designed for racing and should only be handled by tuning pros with the appropriate technical know-how. High-end racing parts often require modifications or machining of certain elements to accommodate the often larger components (larger crank webs, larger intake, etc.). Whether you stick with 50cc or increase the displacement, high-end racing parts offer much higher performance than the original parts and are the most powerful tuning parts.

Note: To ensure the reliability of the engine, it is important that the parts are compatible and that you do regular maintenance on your two-wheeler.