When I installed the additional lighting at the rear of my '81 R65, I used a terminal block from Radio Shack .
The bikes original wires went onto a terminal screw with a ring type crimp on terminal end, then I put ring type crimp on connectors on the ends of the wires going to the brake light, tail light .
If the wiring is shot, make up new wires, the longest should be no more than 12 inches or so .