I believe you can buy wire sets for these old bikes but I have a roll of 7mm copper core wire and figured what the hell. Flat head screw driver solder (not acid core) and a high watt iron 7mm or maybe even 8mm copper core wire something to hold wire (makes it easier) silicone spray Removed the thread part inside the spark plug boot and the resistor thing (save) hit the wire with the spray to help easy it threw the boot. Cut the end off with the disc (save) Desolder it from the piece you cut, remove the retainer and grommet seal (spray with the silicone to help take it off and maybe not break it) feed some new wire threw the boot (spray helps) solder the disc onto the wire. spray the retainer and grommet to help it slide onto wire, also put some die grease around the grommet to help it reseal (its old so use care) reinstall on bike