The fuel capacity of Royal Enfield motorcycles can vary depending on the model. However, the most common fuel tank capacity for Royal Enfield motorcycles is around 13.5 liters (3.56 gallons). This capacity provides a decent range for riders, allowing them to cover a considerable distance before needing to refuel. It's worth noting that specific models or variants may have slight variations in fuel tank capacity, so it's always best to refer to the manufacturer's specifications for accurate information.