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Helicoil reliabillity?

Discussion in 'Technical and Troubleshooting Torque' started by fekkinell, Apr 8, 2010.

  1. Sooo... a CBR929 that belongs to a friend of mine decided to play 'spark plug cannons' and shot one of the plugs out at high revs.

    He's offered the bike to me quite cheap and I just need to fix the thread in the spark plug hole. I don't have much money to spend at the moment, so I'm thinking I might just pull the frame off the bike and get a mechanic to pop a helicoil in for me for the time being.

    Has anyone had any experience in using helicoils to fix spark plug threads and if so, what was the result?


  2. had this happen to my brother on his Z9, he had them all helicoiled and never had an issue there after.
  3. yep will work np, i have used them in a fork where the thread was striped, mate also used it on the sump.

    They work a treat =D>
  4. No idea about that.. but I approve purchasing a 929 :p
  5. for trail bike riders, putting a heli-coil in is like doing the tappets.
  6. I used to be involved with historic racing (cars) and helicoiling the spark plug holes was a question of when not if. In 30years with the product I've never seen a properly installed unit fail, in fact they end up better than the original. If done in situ does produce a bit of swarf so best to make sure the hole is greased and a bit of rag is inserted into the cylinder (piston at top dead centre) to help minimise any getting into the bore.
  7. pm VCM, he had a bad experience with a helicoil in his CB600F donk only 6 months ago.
  8. Thanks guys.

    Might look into having all four done while it's apart then. Sounds like it's the way to go and if it does happen to pop further down the track then that's ok 'cos I'll be rich by then hehe. ;)

    Cheers. :beer:
  9. Nope. The Helicoil is like a coil of wire. The Timesert is a solid sleeve threaded internally and externally. The Timesert will actually seal the thread where the Helicoil will leak between the individual coils that make up the thread (between the external and internal thread form). Okay (Helicoil) if you have a shoulder for a sealing face but no good if you are trying to actually seal the thread ie a stud as opposed to a shouldered bolt. Does that make sense?
  10. Thread insert is what you want.. which is what the timesert is..
  11. Is this the same zauronus that came for a ride to Thompsons dam a few years back with Franky, Ratty, Godfather and a few others? Caning the cr@p out of a baby blade the whole day?
  12. You should also assess what the definition of what "quite cheep" is for the blade.

    It seems like you are going to get a mechanic to do it. Getting in to the plug recess and back out again is probably a $400 exercise and that's if they can do it without removing the head.

    The deep plug recesses may prevent it being done externally and thus the head may need to be removed. Add many more dollars for that.

    So get some quotes from mechanics before you commit to the purchase.

    Also consider how close it is to a major service. If it is in the near future you might want to get the mechanic to do that whilst everything is apart.

    I'm not so sure about the Timesert argument. 4 valve heads are always borderline with valve to plug cracking. Removing more material here is not well advised.

    The plug face provides the sealing with the heli-coil.
  13. Yeah... We're taking it to a mechanic who is going to let us dismantle it ourselves, then he'll do the helicoil bit..

    He is approximating $600ish but that includes his help if we need it for anything like 'dude... I've got a bolt left over... oops.', then add more $$$ for extra requests like servicing.

    Apparently they should be able to do it with the head on, but if not then it just means more work for us taking it apart.

    Quite cheap = $3k for the bike itself... then I pay on-road costs, servicing and repairs. ;)
  14. The heliccoil bit is about $20 worth of parts and about 1/2hour labour. If is done on the bike. The dollars are in time it takes to strip the bike down and reassembly it.

    the mechanic is scamming you. He is basically charging you what he would anyway, but you are doing the work.

    Strip the bike yourself, then take it to a different mechanic on a trailer.
  15. Sorry for this coz it isnt on topic but yeah thats me!
  16. Ah... It's ok. There was some miscommunication. My friend is the one dealing with the mechanic and he confused me. Apparently the mechanic will do the whole engine drop/helicoil bit and we are allowed to use the workshop. Or something. :?

    Thanks for your help though. You've answered a few questions that were swimming around in my head.
  17. Once had one of the Ducati parallel twins, spent more time in the workshop than I did riding it! Anyway one of it's 'troubles' was blowing a spark plug clean out of the engine one day! On the advice of a couple of other riders I took it to a reputable mechanic rather than the 'expert' that had been ripping me off. He said no problems, helicoil will fix it, head has to come off though. I had my doubts but 'bit the bullet' and told him to go ahead. Less than a week later I had the bike back, running better than ever, both plugs helicoiled (he said the other thread was not far behind!) and even the constant blowing head gaskets was fixed (warped head was never noticed by the 'expert'!) .

    After it was fixed I never had a problem again so yes helicoils are bloody brilliant! It was explained to me though that to be done correctly the head definitely needed to be removed. As it turned out this great advice and worked in my favour anyway! Oh and the other lesson was some bike mechanics are brilliant and some 'experts' are crap!