When in a turn, the bike is leaned to the inside to counter the centrifugal force (or is that centripetal). The actual force vector experienced by the bike/rider/fuel/etc is roughly straight down through the tire. This is similar to an airplane in a coordinated banked turn.
Ever have a drink on an airplane? During a turn, the plane is banked 15-20 degrees, yet, the fluid in your cut stays level to the tray in front of you.