A crankshaft is an important but very sensitive part. We are able to balance this part both as to grind and testing.
The crankshaft can be damaged by jamming a bearing of varying load. This is characterized by small hair cracks that arise in the crankshaft. Often, however, these are not visible with human eye. For Smets Motors we can use our advanced testing equipment. a crank of lower load may damage the crankshaft.
When it appears that the allowed values are exceeded by measuring the crankshaft (too rough, oval,…), than we have to resound to cut the crank. This is a very exactly work that requires an extreme precision.
Every time that the piston changes the direction it creates a reaction force. That force is caused by the back and the forth movement of the rotating mass from the piston and the connecting rod. If this force is not the same as the reaction force then it creates a vibration. In a low revolution engine is that vibration not always noticeable. But after time it will damage the bearings and the crankshaft.