A coworker who races cars for a hobby was explaining to me the benefits of using the lowest octane you can. The key is that lower octane burns at a rate that matches piston speed better than the burn rate of higher octane.
But if octane is too low you can get detonation. Detonation occurs at high power settings and at low rpms. It is worse with lean mixtures.
If you're running the engine hard at high power settings, you don't want to go too low octane because you will get detonation. The modern electronics can detect it and adjust the mixture and ignition, but it will cost you in power and fuel efficiency. In the old days you'd destroy your engine with detonation.
Kawasaki says our engines will run on 87. I take that to mean it won't detonate under foreseeable conditions such as full throttle acceleration, high air temps, normal rpm ranges. 87 should be safe to run.
Going to 93 octane should theoretically be less efficient. The only caveat I can think of is if the electronics are compensating for detonation by enriching the mixture, you might get better performance with higher octane when you are running it really hard. Full throttle, hot day, maybe lower half of the rpm range. I don't think these conditions are how many of us ride most of the time.
Last edited by Fly-Sig; 11-06-2015 at 12:09 AM.