Spark plug wire core burnout

[Rainjester]

I'm having an issue with my 53' Pan chopper converted to 12v. I'd been having troubles kickstarting my pan and felt that not enough spark was being produced to fire up the bike.
After a bit of troubleshooting, I pulled the spark plug wire out of the coil and looked at the end. There was virtually nothing there on the end for the center core wire on both spark plug wires as if it has burnt out. I stripped the end and revealed some wire (a couple of cm) put them back on the coil, then 1st kick and bike started! I rode it for a little bit without trouble. Came back later and couldn't start it again, the fresh core that I had stripped burnt again!
Any suggestions on what might be causing it to burn out the core wire on the end of the spark plug wires while attached to the coil?

jester-

[Rainjester]

Umm.. duh.. I just thought of something "why is the wire exposed anyways, there should be a metal sleeve on the end of the spark plug wire before you put it into the coil like a car!"
That'll probably take care of it. Nevermind, I'll try that. ;D

jester-

[sleeper]

Jester-

I see you've resolved your querry. I agree the plug wire needs the 'crimped on' connections. Otherwise if you don't have a SOLID contact, it will arc spark & can cause the burn you have described.
Sometimes when you remove old wires the connector stays "in the coil" & just the wire comes out.
You will know shortly.