Been a mechanic for 42 years and running my own shop for 25 years. I come across this problem every week on alloy engines.
Firstly, always use a SMALL amount of Anti-Seize compound on the treads. These nickel and copper greases are great electrical conductors, so don't get any on the electrode area or the porcelain insulator. Don't bother on cast iron heads because cast iron is self-lubricating due to the carbon content.
Secondly, if the plug is seized, use penetrating fluid. WD40 & RP7 would be my 3rd choices. Rost-Off would be my second choice, be it their freeze spray or standard spray. If the plug moves off the gasket seat, then spray enough down into the seat area to leave a small "puddle" then work it GENTLY back and forth a couple of times then LEAVE IT ALONE for about 15mins to penetrate. Then come back to it and try it again, working back and forth with more spray. Mot times you'll be successful. If it's not happening, you COULD try removing the air filter element, render the injectors inoperative, open the throttle and spray some down the intake to be drawn into the cylinders. Don't swamp it, just a few squirts. The plug is adjacent to the inlet flow, so the penetrating fluid will contact it.
My first choice is always INOX MX-3 industrial grade spray lube. That stuff is close to magical on how it penetrates seized threads and lubricates them. Sure, we've had some that have required cylinder head removal and drilling out, but INOX has saved us so much time and grief on dozens of occasions. We use dozens of cans of Rost-off for general shop use, but the INOX comes out of the cupboard when we need to remove irritating plugs.
My own bike is a 105th Anniversary Road King with 23,000km on the clock. I changed the plugs at the weekend without problem, but did notice that the last third of the plug thread on the combustion chamber end had a black carbon stain which usually indicates that it's been protruding into the chamber or the plug-to-thread clearance is not real close. The new plugs (as specified in the NGK application list) went in and tightened okay, but I might just remove one to check plug tread depth out of interest later. This could theoretically cause a problem if there is a build-up of carbon on the exposed thread and then you try to withdraw the plug, pulling that carbon into the thread of the head, seizing the plug.
If all else fails and you need a thread repair, don't let someone helicoil it. The helicoil will create havoc next time, as they don't lock into the head.
There are a few proprietary brands and styles of plug thread repair inserts on the market and they all work better than helicoils.
We use the TIME SERT repair system, but it has to be installed correctly. Firstly, the correct length insert must be selected. If the insert is too short or too long, then the insert cannot be locked into place on the inside of the head. Second, the operator must use the correct style of insert (flat or taper seat). Third, the operator needs to use the supplied tooling to recess the top of the head thread area so the insert recesses correctly to make sure the washer gasket surface is not compromised. Fourth, a small amount of quality locking compound must be applied to the insert as it's fitted. Fifth, the insert sizing and application tool must be lubricated, because it's not a tapping tool, but simply expands the insert slightly as it screws down the insert. The final part of the process with the application tool rolls the combustion chamber end of the insert out, so that it lock the insert preventing it being drawn out of the head if the plug seizes later in it's life due to no Anti-Seize compound being applied to the plug threads (original problem, remember?). This process results in a permanent and reliable repair, usually as strong or stronger than the original alloy thread.
The Time Sert kit is expensive and the process, although not overly technical or complicated, should really be carried out by an experienced and competent tradesman. You don't need someone practicing on YOUR bike.
Now, prevention is always better than cure. It amazes me how few mechanics use Anti-Seize on plugs installed in alloy heads. No automotive dealerships, that's for sure. However, even worse is the mechanic that's too slack to fork out for a can of Anti-Seize and uses high temp bearing grease instead (hey, it's good for wheel bearings). Might as well use Loctite on the treads of the plugs. The grease bakes with the head temperatures and literally locks the plug in, making the job a nightmare. You can always tell when they've done it because of the stench of the plug tread after finally getting it removed (hopefully).
Well, I hope this helps out and here's a couple of links so you know what I was discussing:
http://www.inoxmx.com/
http://www.timesert.com/html/sparkplug.html
Hi, thanks for everyones suggestions, rang a company called ThreadTech in Brisbane, he came out same day, they are a mobile thread repair company, he got the plug out and saved the thread, however it looks as if it may have been cross threaded, either by the dealer or from factory. I would recommend these guys to anyone who needs to have a thread repaired, or bolt removed, they are very prompt to reply to emails and will answer their mobile phones.
Now the job of putting the bugger back together, gaskets and plugs (with anti freeze) and then shes a goer again....
Cheers
LOL, ANTI SEIZE. Oops........................................
Update on the snapped plug issue, all back together, all new gaskets and plugs, checked and double checked everything, so I fired her up and she was only running on one cylinder, cheked all the connections to the injection system, tried again and now she wouldnt start at all. Pulled rocker cover off, removed plugs and turned her over to chech the rockers and valves, and all seemed fine, back together again and she started, sounded like only on one again, tried to give her a light rev and I have virtually no throttle response at all and the engine light stayed on while it was idling, turned her off and disconnected the battery, as have been told this will reset the computer just in case. Anyone have any ideas on what I can try tomorrow, had enough for today lol
Thanks again for reading
Rosscoe.
Thanks mate, can I find the code myself or do I have to take it to a shop to be hooked up to a diagnostic system???
No mate the bike is stock from factory. Can I find the fault codes by using the "turn on and off 3 times" method and wait for the engine light to flash and then find the code that way??
I might be wrong, but going on memory, try cycling the turn on proceedure four times I think that resets the ECM back to default.
Easy fix if it works and nuthin ta loose if it don't.
Thank you for the help, went out this morning after having the battery disconnected over night, hooked it back up started bike and the same problems existed, no power and it wouldnt rev, anyway while letting the bike idle and walking around the bike checking everything I noticed the connection to the air filter (air flow metre???) was wobbling around, turned bike off pushed on the connector and it was not seated fully, made sure it was seated correctly, started bike and all the issues have now gone, no engine light and she revs freely. Now for a test ride. Thank F##k I dont have to take it to a dealer, life is good again lol.
Thank you to all who offered advice from the original problem of the seized plug to the "owner caused second one" thanks again everyone. Rosscoe
Final outcome is a good one, so happy riding Rosscoe.
