The "tak tak" sound you hear when you stop a motorbike after a ride is likely the result of several factors, including the engine cooling down, metal components expanding and contracting due to temperature changes, and the settling of various parts.
When you ride a motorbike, the engine generates a significant amount of heat. When you turn off the engine, the cooling process begins, and the metal parts, particularly the exhaust system, start to cool down. As the metal contracts due to the decrease in temperature, it can produce a series of sharp metallic "tak" or "tik" sounds.
Additionally, various components of the motorbike, such as the exhaust pipes, frame, or other parts, may slightly shift or settle when the bike comes to a stop. This can also contribute to the "tak tak" sound you hear.
It's worth noting that different motorbikes may produce slightly different sounds when they cool down, and factors like the design, materials used, and age of the bike can affect the specific noise you hear. If you notice any unusual or persistent sounds that seem concerning, it's always a good idea to have your motorbike inspected by a qualified mechanic to ensure everything is in proper working order.