Spark plug cap popping off, burnt smell

[Mattsfz6]

My bike started running really poorly and i smell something burned. Pulled over to see the #4 spark plug cap about half way out of its hole. I clicked it back in and everything went back to normal but it keeps popping off.

I saw another thread with the same problem where tightening the plug fixed it for that user. In my case my plug was already tight in its place.

pulled the plug out to look inside, whats this black stuff in there? is this normal? and is it possibly related?

https://lh3.googleusercontent.com/-...6-no/Screen+shot+2013-09-02+at+2.47.40+AM.png

 

[Mattsfz6]

here is a video of it, seems like #3 also has some crap in it

IMG 0317 - YouTube

 

[TownsendsFJR1300]

The black spots appear to be just very small parts of the cap seals that likely came off when removing the cap(maybe someone with a screwdriver poking at it). I'd put the plug back in in the hole and either blow it out with an air compressor or try and vacuum it out (its nothing major).

Once that's out, make sure the spark plug cap is tight on the wire when turning it clockwise. If its loose, shorten the wire by approx 1/4" and re-install the cap, it should tighten up.

With age/heat, the rubber cap seals get hard and are difficult to install. A little bit of di-lectric grease around the rubber seal will allow the rubber to slip into the valve cover much more easily. You'll actually hear the cap SNAP onto the spark plug. Just wipe off any excess sticking out.. It'll also release easier next time you have to pull the cap/plug.


Please post your results..

 

[FinalImpact]

With the plug being in tight the only reason for the cap to pop up is the lock is ineffective OR the dust seal is too low on the cap.

Move the dust seal up the cap, seat the cap listening for clicks as mentioned above, then push the seal down onto the valve cover.

 

[Mattsfz6]

Thank you for the responses, I'm gonna try what you said and see if the problem persists. :thumbup: