As I studied the resources available, for the F800GS ( not a whole lot) I compared it with the info from DJ, and they all really added a lot of fuel. If you look at the DJ base maps, they are pouring in fuel as well, so there must be something to that. But on the flip side of that, why with a about 30% fuel addition, why am I not seeing a detrimental fuel economy....???? My answer to that, is along my tuner's answer.... It takes a certain amount of fuel/air to move a certain weight or should I say mass along. And I can say with certainty, that with this installed, it takes a whole lot of less throttle, than it did before.