Okay so I have a new to me 2009 F800GS I've put about 1500 miles on and it has just under 10k total miles on it. As I figure out the bike fuel range is a big item to get nailed down. So here's an interesting experience I had the other day when on a weekend trip riding 2-up: 1) Average mileage indicator says I'm getting 43mpg I've reset this about 600 miles ago should be fairly accurate. Yes I know that's kind of low. 2) I reset my "A" trip meter every tank. I'm out larking around and the trip meter says 170 miles. Should be about out of gas, right? 4.2 gallon tank, right? Sure but the little reserve indicator says I have between 40 and 60 miles left (changes a bit) so I keep going for a bit. At this point I'm going light on the throttle and heading for gas.... 3) Around every RIGHT hand corner the bike sputters like it's running out of fuel. Not on the straights, not on the left corner, just on the right corner. The sharper the right the worse it is. Sputters then recovers like it's running out of gas. At this point I'm kind of worried. Right before town there's a real sharp like 10mph right hand corner and the bike flat out dies. Get off the road crank for 20 seconds kind of die. Bike starts back up. 4) Get to gas station put in 3.66 gallons fuel. Full up. Thought the tank was 4.2 gal? And at 43mpg how the hell did it only use 3.66 and get me 170+ miles? So I'm confused. Funky BMW electronics not to be trusted? I'm thinking a couple Rotopax, one on each side of my top case, are in my near future. Anybody have any enlightenment about this? Not that it matters but bike has K60 tires, BMW AF-XiED and Remus header with stock can. I don't expect great mileage with that setup, especially 2-up, but would like to be told the truth... or plan around the lie. Whatever. TIA.