RE: Interference
yup that looks like a ring with a wire lead soldered to it. the question is even if he has that wire and ring, he's saying it does not make contact with the hex on the plug. so the ring and wire do nothing to help, unless he connects the other end of the wire to the motor case, that would close the loop between the motor, spark plug and ignition. Personally I would do away with the ring and wire and make sure the cap is snug around the Hex on the plug. One less wire and solder joint to worry about... I have a CRRC GF50 and in most threads I've read about interferance with running them the solution was to use a hose clamp and make sure the cap is snug on the Hex....
Gene