To be honest, I haven't looked at the KZ1300 fuel tank sender but most senders are somewhat serviceable. There's a stainless steel wire which has a reasonably high resistance wrapped around usually a flat non metallic mandrel or a form for use of another word. Then there's a contact that is attached to a rod which is attached to a float. As the contact moves up and down the stainless wire, it varies the voltage going to the fuel tank level meter.
Usually, the pivot in the float arm will loosen up and then the contact is not riding on the variable resistance wire and you have an open circuit. The repair here is to tighten the pivot so the contact face remains in contact with the wire.
The second common failure more so when the level sender has sat for a very long time is corrosion builds up on the contact face or the outer diameter of the wire and then there's a high resistance between the contact and the wire and again, the level sender is not supplying enough voltage to the meter to register. Cleaning the stainless wire and the contact will cure this failure.
On rare occasions you might find a broken wire (the stainless wire) although one would want to say the sender is beyond repair, it's not. Replacing the wire with the same diameter stainless wire and using the same number of wraps around the core in the same location will cure this failure. Trust me, I've done a few including the one on my 1985 Porsche 928. The replacement cost for a new sender for it was over $400.00 Canadian. cost me $3.00 to fix the original.
For those that understand electrical, the tank sender unit is a simple variable potentiometer.
