Using a higher octane gasoline than recommended for a motorcycle typically does not cause any harm to the engine, but it also doesn't provide any significant benefits. The octane rating of a fuel represents its resistance to knocking or pinging in an engine.
Motorcycle engines are designed to operate optimally with a specific octane rating, which is typically indicated in the owner's manual or on the fuel tank. If the recommended octane rating is 87, for example, using a higher octane fuel like 91 or 93 would not offer any performance advantages or improve fuel efficiency.
The reason for this is that higher octane fuels are formulated to resist premature combustion or detonation in high-compression engines. If your motorcycle engine doesn't have a high enough compression ratio to take advantage of the higher octane fuel, it won't provide any tangible benefits. The engine control system in modern motorcycles adjusts the ignition timing to accommodate the octane rating of the fuel, ensuring efficient combustion and optimal performance.
Using a higher octane fuel than necessary may result in some extra expenses, as higher octane fuels often cost more than lower octane options. Therefore, it's generally recommended to follow the manufacturer's guidelines and use the fuel with the recommended octane rating for your motorcycle.