Good question? Sorry if I'm alittle lengthy.
Use the recommended octane fuel from the manufacturer!
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting
When bikes are put together at the dealership they are adjusting and tuning the bike to factory specs for their location at their altitude. As our bikes are driven at different altitudes the air/fuel mixture changes along with it. For the most part no air/fuel adjustments are needed. However, with major altitude changes adjustments should be made to the air/fuel mixture to maintain peak performance if your intention is to be at location for awhile.
If your bike was normally being driven around sea level the bike will experience a rich fuel mixture as altitude increases and visa-versa a lean condition if your bike comes from a high altitude(like from Denver to Los Angelos).
Being a Flight Instructor the octane question comes up alot. The air fuel mixture is always being adjusted for flight for different altitudes. Most general aviation planes use 100 octane low lead. Inside the cockpit we have a Fuel Mixture Adjustment Knob to maintain peak performance. We can't afford to have pinging or knocking while trying to take off. It would be nice if while we were riding we had a small fuel mixture adjustment knob on our handlebars.
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What does octane mean?