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Spark Plug Stuck?

Discussion in 'Technical and Troubleshooting Torque' started by matty__, Aug 1, 2007.

  1. Hello,

    Trying to replace my spark plug on my Yamaha WR400F, undone it with the correct tool and it seems to be stuck? You put your finger down there and It wiggles around loose as anything but it just won't come out!

    Is there a reason for this? Its my first time replacing.. maybe a hidden trick i dont know of?

  2. I'd say its caught on the washer. Unless the head has got helicoils (spelling?) and its come loose. You'll have to have a look and see (try) whats it catching on.

    Be careful not to push crap into the hole.
  3. Sounds like the same problem as the old man's klr 250 commuter, the socket/box spanner is fouling the cylinder head. see if you are scoring the outside of the tool. For my solution, a $8.55 deep socket and five minutes of careful angle grinder work made a tool with walls thin enough to avoid fouling.
  4. I think that all that is happening is the spark plug spanner is not holding the plug. Mine is like this. It doesn't have the rubber bung that some have.

    You will need to fish the plug out with a pair of pointy nose pliers.
  5. Ahh yes, i had the same problem on am XC 302 Cobra, the rear blugs were a pr1ck to get out between the extractors.

    I ended up with a bit of rubber air hose as my 'special' spark plug removerer/inserterer tool
  6. Thanks for the replies. No unfortunately its not a case of just "pulling" it out, obviously ive tried that :p

    I've tried long nose pliers etc, my finger and moving it around tried to lift it up and flat head screw driver.. u can't lift it up one bit. Definitely stuck. :mad:

    Anymore suggestions?
  7. You could try starting it up, I imagime a 450 single would have enough compression to move it. Might pay to put a rag or something over it though cos if it comes out it will come out in a hurry.
    If that doesn`t work the thread in the head may be stripped. Do you know who put the plug in ? If it was overtightened then that could have caused the damage.
  8. I hope the thread isn't stripped, but I wouldn't be surprised since about 4 other threads have been repaired on this bike since i've owned it (4 or so months).

    The reason im replacing it is because it wasn't starting after i serviced it, which is a bit sus :shock: but had a new spark plug to put in anyway.

    By starting it will that shoot it out? Do i need to put the cap on?
  9. no leave the cap off. you dont want the fuel/air mix comming out the spark plug hole with a ingition sorce right there.

    has the bike had the rocker cover off recentley or somthing? you need to try and have a look and see whats stoping it.
  10. We got it off.

    I used my friends spark plug tool which is newer than mine and it came straight out!!!