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Little goes Big. - From Spark plug to Cylinder head

Discussion in 'Maintenance and Servicing' started by dmrmgl, May 4, 2014.

  1. Dear NETRIDERS.

    Id like to post my 1st ever in life time cylinder head work.

    It come with spark plug at the first time.

    I wanted to replace a spark plug on front bank of my VTR 250.

    and see what happened on attached file.

    Seating in head for long long time and FXXKed. It came out without its THREAD.

    so I decided to take off cylinder head to drill and re-thread.


    Attached Files:

  2. Why didn't you just pull the thread out?
  3. Because that wouldn't make for a good story incontinentia. Easy out and 30 seconds work is too easy
  4. I couldn't because broken thread was siezed in the head.
  5. maybe you are seized in the head
    • Like Like x 1
  6. Looks like a well looked after well maintained spark plug. Can't understand it breaking off.
    • Funny Funny x 2
  7. Like RRdevil said, an easy out should have worked. A tap with a hammer probably would have done the trick for the thread. There's usually an easier way if you give a few minutes to think about something. Did you have to use a helicoil?
  8. after bit of time with easy out, finally got the thread.


    as you can see its thread is damaged. so yeah i just tap to re-thread the cylinder head.
  9. #9 dmrmgl, May 5, 2014
    Last edited: May 5, 2014
    lucky me not to need helicoil. :D

    while I was re-threading, found that the original thread in head wasnt damaged. I put re-thread tool in there to clear out all metal scraps.
  10. Lucky.

    Good work.
  11. Good job.
  12. nothing to see
  13. Erm how did this get here?
  14. Curse of multiple tabs. Thank you. Fixed.
  15. Is this a thread about a thread ?
  16. thread^2
    • Like Like x 1
  17. Dear NRDRs

    I was being lazy to post some Ive done till now but yeh, here some infos.

    Basically I put new spark plugs and new head gasket.

    I inspected timing belt and tensioner, they r still in good condition even my bike have done 98k KM on odometre though.

    However I found piston with full of carbon deposit on the top


    Also, on the surface of in,ex valve, there was carbon deposit too.


    well, Honda VTR250 workshop manual suggests to put some patrol on the carbon deposit but it didnt work well on my engine.

    Lucky I had a can of injector cleaner so i put it on there and I could remove some of dark matter a bit.

    putting head on, timing, all bolts with torque wrench.


    before you take off the camshaft, bring a little white correction pen and put marks on chain and sprokets.

    It made me timing job so easy. i think it took only 2~3 minutes to do for correct timing job.

    as I didnt have a new rocker cover gasket, I put liquid gasket on old rocker cover gasket and install it.

    after all job of put-everything-back, coolant topped up, bleeding coolant a bit,

    Finally my bike hit the road.

    run healthy.
  18. Good job. Not many people would even attempt it. Although the threads can be cleaned up with the head on, there is a risk of swarf falling into cylinder & getting stuck under a valve. So it is probably better to remove the head.
  19. Ye thats right. Thread debries may fall into the cylinder and damage wall. It was a good experience though :)