From - Motegi mysteries - MotoGP - Motor Sport Magazine
"Braking and corner entry are now hugely important in MotoGP, so it was no surprise to see the layout of Yamaha's 2016 YZR0-M1 prototype ridden at Motegi by wild card Katsuyuki Nakasuga. In its search for better braking balance, Yamaha has a fuel tank that's about three feet long. The tank extends all the way from the rear shock into the seat hump, with the filler cap mounted in the hump; in other words shifting the fuel load as far back as possible."
Check the location of the fuel filler cap on Nakasuga's bike versus that on the 2015 M1
"Braking and corner entry are now hugely important in MotoGP, so it was no surprise to see the layout of Yamaha's 2016 YZR0-M1 prototype ridden at Motegi by wild card Katsuyuki Nakasuga. In its search for better braking balance, Yamaha has a fuel tank that's about three feet long. The tank extends all the way from the rear shock into the seat hump, with the filler cap mounted in the hump; in other words shifting the fuel load as far back as possible."
Check the location of the fuel filler cap on Nakasuga's bike versus that on the 2015 M1