Yes, you can generally use gasoline with an octane rating of 91 in a motorcycle. The octane rating represents the fuel's resistance to knocking or detonation. Most motorcycles, unless they have high-performance engines or specific requirements, are designed to run on regular unleaded gasoline with an octane rating of 87 or higher.
Using gasoline with a higher octane rating, such as 91, typically won't harm your motorcycle's engine. However, it might not provide any significant benefits either, as long as the engine is designed to run on lower octane fuel. Higher octane fuels are more commonly recommended for vehicles with high-performance engines or those that require it due to specific engine designs or turbocharging.
It's essential to consult your motorcycle's owner manual to determine the recommended octane rating for your specific model. The manual will provide information on the suitable fuel types and octane requirements. Following the manufacturer's recommendations ensures optimal performance and longevity for your motorcycle's engine.