Check your fuel pump....
Sounds like a dead pump.
First, make sure your battery isn't the culprit, really dead batteries may not get a full charge from a trickle tender regardless of how long they're on, or it might be a dead cell. Use jumper cables to jack in a known good 12v.
Then take apart the three wire connector under the L subframe rail under the driver's seat, jumper 12v battery directly to the pos and neg pins (the third pin is the fuel level sensor). Have the key on and the kill switch on when you do this. The pump should immediately spin and pressurize the lines enough to start.
If not, check the pump relay (three box black box atop the ECU under the seat), there's a pinout check diagram in the manual that'll guide your resistances.
Otherwise all I can think of is check your lockout switches...clutch, kickstand.
If your pump is dead, there's a concise writeup on here on replacing the pump assembly.