One of the not-so-uncommon points of failure in K bike wiring is that the connector for the fuel level sender and fuel pump gets flaky or goes bad. One option for replacing this connector is to use a standard four lead SAE trailer connector. The wiring gauge is more than sufficient, it's fairly weatherproof and if you get the one with white, yellow, green and brown wires then you can match that up pretty closely to the factory wiring colors.
I recommend soldering and the double heat shrink tubing the wiring connections. Here's a picture of one that I did:
(http://i278.photobucket.com/albums/kk91/electro_handyman/Bike%20Tech/flsco1.jpg)
edited by scott_ 10-12-13 to replace missing photo's