I looked at that on the CRRC ignitions, but I could find no key to getting them off. The wire is shielded the entire length, which means it is grounded to the metal cap. I was afraid I would mess up that ground if I forced it off. I'm thinking the CH ignition is much the same. I guessed that they were pressed or crimped onto the wire. I noticed the ignition on another model I have has a ground wire running directly to the metal plug cap and no shielding. I would expect I could unscrew this cap.