Spark Plug ring and end of electrode boke off in friends KX125 - what to expect?

[The^^Rock]

Hey all,

Had an awesome days riding today, all was going good until we decided to pack up and go home.  On the way home both me on the CR and my friend on his 99 KX125 were riding 5th pinned, flat strap.  All of a sudden I can't see him behind me anymore, so I go back to check up.   Anyways there he is kicking it over trying to start it.  I asked him what happend and he responded with "My back brake locked".  Now im pretty sure that that wasn't the case, and indeed he did seize his bike.  The bike could and can be still kicked over so maybe she unwleded herself as well in the process.  Anyways we walked the bikes back home.

As soon as I got her in the gararge I took out the plug for a squiz.  Didn't look good at all.   Half of the ground ring was missing along with THe end of the electrode. I proceeded to do a compression test and get a huge reading of 37 PSI.   And no my gauge isn't falty, im still getting a 185 reading on my CR.  

Ok now my friend has told me he dosn't want me to touch it, and that he will take the bike to the dealer after this long weekend is over.  Now its going to be a long wait, becuase the dealer dosn't open until Wednesday, due to easter weekend.  So what im wondering is how bad could this damage be, and what happens to these broken peices of plug floating about?

New piston and rings is a fact, but how would the barrel have held up?  Is it possible that it can be bored or will he be up for a newie?  Also where would these peices of spark plug most likey have gone?  Would they have been blown out the exaust or could they have made their way into the bottom end?

Pic is attached, although quite blurry.  Ill try to make a diagram up.

Thanks all

Jim :laugh:

 

[The^^Rock]

This will explain it better :)

 

[marcusgunby]

It could be a minimum of new piston kit and head mods to repair damage, also likely it will need the bottom end splitting to ensure no bits have got stuck.It may have done big damage to the cylinder as well-a eric gorr big bore is the most effective cure.Also you need to find out why it broke, many reasons for this,
detonation
air leak
too lean jetting
too hot a plug
too advanced timing
the list is long im afraid.

 

[bclapham]

i wonder if this current spate of plug failures is connected to the constant demise of the quality of pump fuel?

although, pumps fuels are running the similar specs to previous years, as blending technology improves, they work out how to put more crapola into a pump blend whilst staying at the same octane. I dont think this is just isolated to one country either.

 

[holeshot]

As well as ensuring the normal things are correct, some have been switching to the Suzuki RM 125 plug (designed to resist this type of failure). I've modified your pic to illustrate this. Note that the RM plug also has a slightly more "stubby" electrode than the stock plug in my KX.