The fuel economy of a KTM Duke motorcycle can vary depending on various factors such as the specific model, riding conditions, riding style, and maintenance. However, as a general estimate, KTM Duke motorcycles typically offer a fuel economy ranging from 25 to 30 kilometers per liter (km/l) in mixed riding conditions.
It's important to note that these figures are approximate and can vary based on several variables such as speed, traffic conditions, terrain, and individual riding habits. Additionally, fuel economy can be influenced by modifications, tire pressure, and maintenance practices. To get more accurate and specific information about the fuel economy of a particular KTM Duke model, it is recommended to refer to the manufacturer's specifications or consult with KTM dealers or current owners who have firsthand experience with the specific model you are interested in.