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HELP!! Broken Spark Plug

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Was reshimming my valves in a 15 crf250r last night and after I got that done I went to check the plug as it hasn't ever been changed. Plug didn't feel overly tight just snug, unscrewed it and the end of the threads/ground electrode is still stuck in the head. Any ideas on how to get it out?? I plan to just remove the head so nothing falls into the cylinder. While I'm in there would it be wise to replace the piston and rings as the bike has 25 hours on it?

Thanks for any help!

IMG_20190418_215046.jpg

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Yes if I were you I would remove the cylinder head and don’t kick the bike over until you have everything out to lower the risk of damage

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Yea Im not going to try kicking it.  Any ideas on how to remove the broken piece? I was thinking tap a big flat head into it and try to screw it out the bottom of the head if it's threaded all the way through

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I don’t have a sure solution to removing the broken piece, but tapping a flat head into it and backing it out should work

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36 minutes ago, HondaMoto47 said:

Yea Im not going to try kicking it.  Any ideas on how to remove the broken piece? I was thinking tap a big flat head into it and try to screw it out the bottom of the head if it's threaded all the way through

Soak it with PB Blaster first and maybe back the way in goes in but you will see how far its threaded in once the remove the cylinder.

Did ALL the rest of the spark plug come out?

When you get this sorted you could use a bit of anti-seize the the new spark plug threads and obviously it only needs to be snug tight.

Good luck and I'm following

Edited by filterx
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Yes the rest of the plug came out fine, unscrewed it with my fingers on the socket extension. The only corrosion was a little between the washer and plug body, threads looked fine. Never seen the the last 1/4" get stuck and shear off lol. I'm guessing the ground electrode is still attached to the stuck part but will find out when I pull the head. I'll post a pic of the plug tonight when I'm off work. Definitely going to apply antiseize. Just hope I don't have to buy a new head

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1 minute ago, HondaMoto47 said:

Yes the rest of the plug came out fine, unscrewed it with my fingers on the socket extension. The only corrosion was a little between the washer and plug body, threads looked fine. Never seen the the last 1/4" get stuck and shear off lol. I'm guessing the ground electrode is still attached to the stuck part but will find out when I pull the head. I'll post a pic of the plug tonight when I'm off work. Definitely going to apply antiseize. Just hope I don't have to buy a new head

As I said you will know better once you get the head off and did only 1/4 of the plugs thread break off cus that is really weird? Random plug pic.

Clipboard01.jpg.b2ee26739701c8df2c99cd8c4b2ec885.jpg

Was the plug the correct iridium?

I've never personally had the head off my bike so not sure how far the plug goes in.

Happy Good Friday and I'm off work and slightly bored cus its pissing rain and not out riding

 

 

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Yea, the last little bit of the metal twisted off. The porcelain and electrode all came out fine. There is basically a metal ring with the ground loop still in the head. I'm guessing from arrow down on your pic is about is what's still threaded in there

It was the stock plug so I would assume they put the right one in from the factory

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7 minutes ago, HondaMoto47 said:

Yea, the last little bit of the metal twisted off. The porcelain and electrode all came out fine. There is basically a metal ring with the ground loop still in the head. I'm guessing from arrow down on your pic is about is what's still threaded in there

It was the stock plug so I would assume they put the right one in from the factory

The rubber cap has a good seal but I put a bit of WP grease on it when installing. I can't tell from your pic but on my 05 it has a drain hole in the head in case water etc gets passed the rubber cap. Looks like you got some dirt at the bottom of the head and something you might want to check

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I would soak it in Triflow then use an easyout with the proper tap socket and an extension.

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You should remember : something caused the last few threads to seize up and break the plug off. I suggest that you take it apart and look at the remains of the plug from the inside of the head. If you don't,the threads might be compromised and you'll think that all is well by just assuming the broken parts being removed will fix the problem and that's when it goes really bad. A PIA for sure ,but an education too.

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34 minutes ago, Wally_Tunison_in_N.J. said:

You should remember : something caused the last few threads to seize up and break the plug off. I suggest that you take it apart and look at the remains of the plug from the inside of the head. If you don't,the threads might be compromised and you'll think that all is well by just assuming the broken parts being removed will fix the problem and that's when it goes really bad. A PIA for sure ,but an education too.

^ agree on removing head,checking head plug threads,and antiseize on new plug

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Just now, Mike3025E said:

^ agree on removing head,checking head plug threads,and antiseize on new plug

More work but...then you know it will be right when u go back.

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The head is definitely coming off, not going to risk anything falling into the cylinder and I'm putting in a new piston/rings while I have the head off.

Here is what the rest of the plug looks like, will pull the head off tomorrow.

IMG_20190419_230826.jpg

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Dag on.yeah hopefully it will be ok.chase or tap threads and if they are ok i would torque your new plug in the head with it still off.i always torque on aluminum stuff.especially on these front engine covers we work on here at international

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13 hours ago, HondaMoto47 said:

The head is definitely coming off, not going to risk anything falling into the cylinder and I'm putting in a new piston/rings while I have the head off.

Here is what the rest of the plug looks like, will pull the head off tomorrow.

IMG_20190419_230826.jpg

Have you owned the bike since new and first time changing the OEM spark plug?

 

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I'd take the head to a machine shop and have them remove the portions that is left.

My guess is the wrong plug was in it, had threads extending into the combustion chamber and they carboned up, jamming the threads and snapping off due to excessive force once past the beginning of the porcelain.

To remove, I'd use penetrant with an easy out carefully from the combustion side.

Any time you remove a plug, once a quarter turn loose, it should come out the rest f the way with just your fingers. If it is stiff, back it out a little, thread in back in, repeat. Each time it should move more. It not, you need to use pentrating fluid and probably pop the head off.

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9 minutes ago, William1 said:

 

My guess is the wrong plug was in it, had threads extending into the combustion chamber and they carboned up, jamming the threads and snapping off due to excessive force once past the beginning of the porcelain.

 

The threads and what's broken off looks really long to me BUT hard to tell from the OP pic.

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Yes bought the bike new from the dealership. It's only the wrong plug if the Honda didn't put the correct one in. I wouldn't think there would be that much excess carbon to build up as I run VP u4.4 and the efi map has been adjusted by Tokyo Mods for the mods on it. I'll see when I get the head off later

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