Plug wire oops

[n10city]

Okay, I was in the middle of changing my spark plugs when I accidentally pulled one of the wires out from the coil situated at the front of the frame. When I attempted to remove the cap in order to put the wire back in I butter fingered it and it fell down into the radiator fan. Ugh! So after going through the tedium of removing the radiator in order to retrieve the cap I found that there was no, I don't exactly know what to call it so I will go with rubber grommet, inside the cap. You know, the little rubber sleeve thing that goes around the wire to more or less keep it in place when the cap is screwed on? Anyway, I've searched and have decided that for whatever reason it is gone and I am trying to decipher if it is possible to buy another one. Anybody have any ideas?
I've included a photo of one of the other wires to help with my description.

 

[captain jack]

Try self amalgamating tape, it's got to be worth a try. (clean the butter off your fingers first though)

 

[n10city]

Thanks I'll give it a try. Good idea that.