Here's every tankful's mileage (in mpg) since my stock 2017 Z650 was new (about 4000 miles total): 46.5, 46.6, 47.0, 58.0, 50.9, 48.2, 49.7, 49.5, 51.2, 53.9, 54.9, 57.8, 64.5, 58.9, 50.4, 51.5, 50.0, 50.9, 47.8, 49.0, 49.1, 45.3, 52.4, 46.6, 50.6, 47.1. I use 87-octane E10 gas. The first set of numbers in the mid-40s probably represents break-in friction within the engine. The high 50s-plus were during long road trips. The second dip into the 40s coincided with my riding style becoming more aggressive, and I also switched to synthetic oil. If the last three data points represent a well-broken-in engine and rider, I'm looking at an average of 48.1 mpg. When the polar vortex and road salt go away, I'll resume taking data.
As for the average mpg indicator, I read in the owner's manual that, unlike in my car, it does not reset with the trip odometer. You have to reset it specially (hold right button while it is displayed), which I have never done. My gut impression is that it reads high.
Last edited by nedfromPA; 02-13-2019 at 10:07 PM.
Reason: remove extra blank line