I just fitted a brand new fuel level sensor (bike previously did not have one) just a second fuel tap. Now the warning light is permanently on even with full tank. I removed the sensor from the tank and plugged it into the loopm. Ssensor worked correctly ie as i lft the sliding level sensor the light goes off. Re-fitted it into the tank and permanently on again.
the outer part of the sensor is able to move up and down without any contact to the threaded part in the tank? It may stuck in the down position which is 'empty'
If that is checked i would suppose some troubble in the wiring