Originally Posted by Bob Mac 18704
If this is indeed what you are doing then you've been misinformed about the install of the plug wire. On the top of the plug is a barrel shaped threaded nut. For some unknown reason they have these crimped on. You must unscrew this nut from the plug with a pair of pliers. put the plug in a vise and be careful not to break the white insulator. once you have the nut off, put the plug into the cap taking notice that the little spring thing grabs the threads on top of the plug. Your plug wire should never fall off if this is done. Then proceed to put the plug back in the bike. Hope this helps
That's good sound advice for installing the plug and wire. I assure you, it doesnt need a chunk of foam to stay on.
The problem I wanted to solve is that even installed correctly, there is some wiggle in the cap. When vibrations are just right, the threads on the cap can float enough to cause misfiring. It runs smoother with some pressure on the cap and wasnt expensive.