It is a large cylinder - shaped gear that rotates directly with the motion of the crank attached to the crankshaft and maintains its mobility by exerting the power it receives at ignition time for engine rotation at other times. It maintains engine balance with the crankshaft.

For most models, the starter dynamo provides the first movement necessary the starting system. It has the shape of a fan.

Typically, cast iron is used. Its flaws are 'Skewness Cracks and Friction.' If tolerance limits are not exceeded, it can be repaired on a flywheel grinder.

Apart from mechanical losses such as friction, energy losses occur compulsorily on surfaces where motion and forces prevail in energy and construction machines due to construction and operating conditions.

In general, flywheels can significantly reduce energy losses, which are more common in turbo and rotating part machines. Even when the operating conditions are completely smooth or the forces do not change, a flywheel is needed in rotating machines due to the imbalance in the construction of the parts.

The most important feature of the flywheel is that the energy that would otherwise be lost can be saved in its body and used when needed. A general flywheel should have the geometric shape of a cylindrical disk with a large diameter and a small width. The flywheel should be placed in the system with the greatest number of cycles possible. If this placement is not feasible for some reason, it should be in a rotating position close to the highest maximum velocity. Under these conditions, the flywheel is in a position to benefit the most amount of energy within the system.