In general, it is recommended to turn off the fuel supply to your motorcycle when it is not in use for an extended period of time, such as overnight or when stored for an extended duration. This is especially important if your motorcycle is equipped with a carburetor rather than a fuel-injection system.
The primary reason for turning off the fuel is to prevent fuel leakage and potential fuel-related issues. If the fuel is left on and the motorcycle is not running, there is a possibility of fuel leaks due to deteriorated or worn-out seals or float valve in the carburetor. This can lead to fuel flooding the engine, resulting in difficult starting or even engine damage.
By turning off the fuel supply, you reduce the risk of fuel leakage and minimize the chances of encountering such issues. However, if your motorcycle has a fuel-injection system, it typically has a pressurized fuel system with better seals and less risk of leakage. In such cases, turning off the fuel may not be necessary.
It's important to note that this advice may vary depending on the specific motorcycle model, so it's always best to consult your motorcycle's owner's manual for manufacturer-recommended procedures and guidelines regarding fuel management and storage.