If you're planning to leave your KTM Duke 390 motorcycle unused for an extended period of 2 years, it's generally recommended to take certain precautions to ensure its longevity and proper functioning upon your return. Here are some suggestions regarding the engine oil and fuel:
Engine Oil: It is advisable to change the engine oil before storing the motorcycle for an extended period. Fresh oil helps prevent internal components from corroding or experiencing other issues that can arise from contaminants or degraded oil. Additionally, consider removing the oil filter and replacing it as well.
Fuel: It's generally recommended to drain the fuel from the motorcycle's fuel tank and fuel lines before long-term storage. Fuel can degrade over time, leading to varnish buildup and other problems that can affect the engine's performance. Draining the fuel tank and carburetor (if applicable) helps prevent these issues. Running the motorcycle until the fuel tank is nearly empty before storing it can facilitate this process.
By following these steps, you can help minimize the risks of deteriorating engine oil and fuel causing potential problems during the storage period. Upon your return, ensure you refill the fuel tank with fresh fuel, install a new oil filter (if removed), and change the engine oil before starting the motorcycle.
It's also a good idea to consult the motorcycle's owner manual or contact a local authorized service center for specific recommendations tailored to your KTM Duke 390 model. They can provide you with the most accurate advice based on the manufacturer's guidelines and specifications.