*** the use of the camshaft***
Basically, the camshaft component serves to regulate the duration of the valve opening and closing. opening the valve opening determines the amount of fuel and air entering the combustion chamber. When the camshaft goes well, there are no obstacles in the engine speed. The higher the engine speed, the faster the camshaft rotates and makes the valve open and close very quickly. If the camshaft is damaged, the motor will lose power because the opening of the valve cap to put fuel and air is not perfect anymore.
It's good for motorcycle owners to keep the camshaft durable and let your motorbike away from damage.
The conclusion is that there is a strange noise in the engine quickly check to the nearest workshop.