The sender may be bad. To check , find sender wire plug and disconnect, above fuel tank, combine both wires going to the gauge using jumper, then turn key on =gauge should read full. If it doesnt look for bad ground and sender wire. If it is at full then bad sender. To replace sender you need to remove aft seat back remove 4 brackets on tank. doing this on a empty tank. tilt tank, r+r sender.
MFU001154002 SendingUnit,FuelTank#2616,12v,E21,E22,X22 = $75.19
Or maybe it will start to work again.