I get 36-38 mpg running 75 mph. 2010 model, k&n filter, Jardine slip on and i'm 200 lbs but the area is hilly.
Had the valves checked and changed the plugs recently and the plugs were perfect light tan so not worried about gas mileage.

Do what I do and don't give a shit about mileage. I put on 1000 miles per month easy. If I wanted to get good fuel mileage I certainly wouldn't have bought a zx14. My bike is a beast and if it wants to such fuel like a 2 dollar ho....so be it. If you are that concerned about bottom line of fuel expense, go with the 87 octane. That is the equivalent of 10 more mpg.

Joel.

Every time I ride past ANY other bike I get street credit big time.....worth every penny.

I would never run 87 on a high compression motor, maybe 89 octain