We just got back from a 4400 mile Western US tour, both bikes performed flawlessly. The gas tank on the 800 seemed to be 20% smaller than the 650. Odd? yes, only because the 650 got 20 to 25% better gas mileage than the 800. Every time we filled up the difference showed up. 800 running premium and the 650 regular. De- tuned 650 ? I sure would not re-tune it. Something must be wrong.
Colorado, Wy, UT, ID,MT, ID, WA,OR, CA, NV,AZ, UT and back to CO, Great trip 25 days.