All,
I went in my gargae with some spectators (ended up looking like an idiot) for my usual routine start up (893 Blade). I decided to take the plugs out to clean them and spun the engine a couple of times as I haven't started it for the last two weeks. When I was re-intsalling them I noticed that two kept on rotating freely (using my hand). I inserted a long nose and pulled the plugs out. To my disbelief the plugs threded part was sheared off and now I have the threded part still inseretd in the head.
Q: Did anyone encounter such problem? The plugs are those recomended and they are brand new. I used them last fortnight to synchronise the crabs. Beside scratching my head on how to take the threded part out without removing the head (well I have a plan) I am worried tahat this might happen again.

Any help?

That's a PITA! How R you going to get them out without either taking the head off or ending up with loads of metal in the engine....

Seems strange for that to occur- I'd try sending them back to the manafacturers [with explanation] and get some freebies (at the very least)...

youve probably overtightened the thread

and I wouldnt worry so much

2 weeks and you took the plugs out ?

most people leave the engines for a lot longer without a second thought

I'd be worried that there are shards of metal in the cylinders.

Overtightening sounds like it may be the cause. Most things on an alloy block only need a few Nm. It isn't a lot at all.

Yep sounds like you've overtightened them unfortunately Phil

Its realistically going to need the head taking off to ensure there's no metal in there, but at least the plugs threaded themselves, not the head!

I think I understand this as, The plug has broken in half leaving the main body in the head, not I've strippeed the thread in the head, please confirm........

I think Reman is correct - in which case there would be no metal down the bores & a careful go with an easy out should remove the offending bit. You've definitely overtightened them, quite lucky they didn't just blow themselves out of the engine as they must have been cracked almost thro'

Ah ok, if that is the case then yep you might get away without a head off

Has the electrode come out with the hexagon on the porcelain? That's weird but you should be able to knock something into them and just turn them out.

SORRY!! My original thread didnt mean not to worry about whats happened now as I would be worried

but I wouldnt have worried about leaving my engine for just two weeks

I,ve only seen this once before.... but this was on a fiesta where the plugs hd been in for years.

We got a bit of tube and welded it to the threaded end and were able to unscrew, not really an option 2" down the hole on a blade head...

Its a bitch !

I wouldn't worry a bit about 2 weeks. Many store their bikes for 6 months at a time without engine trouble.

I've seen worse though. A mate of mine was having a right time getting a plug out. Turned out he cross threaded it. The end result what "oh well its only an XS650 just screw it back in again". :-)

This is a common occurance on old Ford HCS engines when the plugs have been left without changing for LOTS of sevices.

If your plugs are taper seat plugs then have they left the taper in the head?
If this is true then you will need to release the taper first by carefully drilling out with a drill bit the SAME diameter as the narrowest part of the taper. Fill the flukes of the drill with grease and get some down the bore of the plug remnants. Then carefully drill out till you just relaese the taper. (carefully means slowly & frequently cleaning drill flukes & re-greaseing.

When taper released or if no taper then carefully tap a Torx bit into hole in plug and use to unscrew thread from head.

This usually takes me about 10 mins start to finnish on a HCS engine.

Hope you get it sorted.

once had an audi and cross threaded the plug, could not be arsed taking head off so re tapped it with hoover sucking away most of the bits.
needless to say it broke but the crank snapped under extream abuse from too much NOS. .
sorry but that does not help you .

As with Jolly on this one had this occur with a ford KA twice and a Fiesta however i got them out by using an easy out .

Providing the entire ceramic core is out i then got a hoover and sucked any crap out of the plug area before putting the easy out into whats left of the plug and removed it once out i then hoovered it area again and put a new plug in.

If theres not electrode parts left in then youl be able to get a bigish easy out in there to remove it. Should be an easy job.

They must have been done up bloody tight to have done that...... Just a little nip up is all they need.

''Q: Did anyone encounter such problem? The plugs are those recomended and they are brand new. I used them last fortnight to synchronise the crabs''

I blame the crabs, those pincers can do an awful lot of damage when synchronised!

Seen it a lot with NGK plugs..

Since it seems rather easy to take the threaded portion out of teh head, can someone tell me how to do it?

Hi Phil

You really need something like an "Easy Out" extractor as mentioned above.



As you can see, they are a bit like a drill but tapered, and the "cut" direction is opposite to a regular clockwise thread. The idea is usually to drill into the bolt / thread you're trying to extract, but as your spark plug end is already hollow you can skip this bit. What you then need is an easy-out that's taper allows it to sit in the hole, but not pass through. You then wind it anticlockwise into the spark plug end, and as it goes further in it grips, and as you're turning anti-clockwise it should eventually unscrew the threaded part.

Chris

[Edited on 5/5/07 by ChrisGamlin]