Topic: gooey spark plug wire

[mmmpeanutbutter]

So I've been having some problems with my CB400F.  I wanted to replace the resistor caps a few weeks ago and just got around to it.  When I got back from my ride, I popped off the caps.  The wire for the 4th plug was all gooey on the inside around the wire.  I thought maybe I shouldn't have pulled it off when the bike was still hot, but I checked the other ones and they were fine.

I got the new caps and I was just going to trim each wire 1/4 inch and re-attach.  But when I went to the #4 wire, it was still gooey inside (harder gooey, not as soft as it was before.  before you would get the goo all over your fingers).  So the wire indide is all mixed up in this soft melted wire.

I don't want to keep cutting if I don't have to (I can only go so short before I have to start splicing wires).  I also don't think I should just ignore it and put on a new cap. 

Any ideas?  I think I would be better off knowing what the cause is so that I can fix it before I put new caps on or splice anything.  Thanks.

[ejand22]

I noticed the same thing on my bike the other day.  I was changing the plugs and one of the caps came loose from the wire.  It was gooey inside as well.  It looked as though the previous owner cut the connector off of the end of the wire and just jammed it into the cap.  I needed to get somewhere so cleaned out some of the goo, jammed it back in there and it's worked fine ever since.  New wires are on order though...

[bike54]

hi
the answer is old age
plastics on the era of our bikes where not as stable as they are now and after time they brake down some types turn to dust but a lot go goey especially high tension leads i would replace them all with modern ones

merv   

[bistromath]

Our plug caps are the screw-on variety. The stranded plug wire just screws into the cap. Yes, it's sort of odd, but it works.

Many people use silicone grease (dielectric grease) to prevent water from creeping into their caps and shorting the spark. Perhaps it's just grease? Otherwise, I suppose the plastic could have broken down but the caps are made of pretty good rubber.

[TwoTired]

Just a theory. 

But, I know that many polymers break down with exposure to ozone.  Ozone can occur when an electrical arc occurs in the atmosphere.
Perhaps the screw in connection became faulty and arcing occured between wire and screwpost?  The resulting ozone and heat broke down the insulation and it is reverting back to its liquid state?

The insulation likely began life as a liquid before it was polymerized.