Connector melting 1980 KZ 440

1980 KZ 440 has a connection under the seat with three white (? with stripes) wires that come out of the rr. The connector is getting hot and melting. The bike is charging. I did a diagnosis on the rectifier and it is indicating bad ground to rr. I cleaned the ground connections and I cleaned the connector with the 3 white wires, and it's still melting. Any ideas? Also, I think it's unrelated but maybe not, the left spark plug has weak spark. Any guidance would be greatly appreciated. Thanks

These connectors melt do to high resistance in the wiring terminal connection, building heat/ melting.
You need to replace the connection, and the wiring back a few inches minimum, any wire that feels stiff and hard has been heat damaged.

Check your plug cap resistance. Rerun your wires with a fine tooth comb. Do you have testing equipment and understand its use?. good luck

Thanks... started going through the wiring and cleaning contacts. Noticed the following.... a part is missing from wiring on the right side.
see the dangling wires? white with black stripe.

both connectors are female and made to hold 2 male "bullet" connectors.

this is where one comes from.

Any ideas? Thanks.

Unfortunately, it's pretty much normal for those stator wire connectors to overheat and burn the shielding jackets like described. Only thing you can do is make sure the brass terminals inside are clean and free of excessive resistance. Also make sure the R/R ground path is clean of corrosion too. As for those extra wires, you may want to look at your wiring diagram to see if they could be accessory feeds. My 750 has them anyway and I seem to think they are white/blue like those.