Author Topic: I'm going to go out on a limb and say that this plug is not gapped correctly.  (Read 2872 times)

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Offline Lenny55

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Just pulled my #4 plug, and this is what I found.

The ceramic is broken around the electrode and both will move around in and out if you tip the plug upside down.

I'm guessing those missing bits of ceramic are now in my cylinder?  Did this just happen as I was taking it out do you think?  The bike has been running pretty good thus far, not sure if that plug would still spark or not. 

The plugs were new last year.

Whaddya guys think of this???
'73 CB500

Offline leogriss

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Replace it! ;D

Offline Whaleman

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One thing I have done is to tape a 1/4" dia length of gas line to the end of a shop vac and you can reach in and get the piece if it is in there. Dan

Offline ksmith0034

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One thing I have done is to tape a 1/4" dia length of gas line to the end of a shop vac and you can reach in and get the piece if it is in there. Dan
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Offline Lenny55

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It was getting replaced anyway, that's why it's out ;).  I just tried that exact thing whaleman, not sure if I got anything though.

I imagine a piece of ceramic would wreak havoc on a cylinder wouldn't it?
'73 CB500

Offline 75cb550 (kyle)

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It was getting replaced anyway, that's why it's out ;).  I just tried that exact thing whaleman, not sure if I got anything though.

I imagine a piece of ceramic would wreak havoc on a cylinder wouldn't it?
yeah...

Offline cbr-eric

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ehhh, I am unconvinced. we need a pic of the plug with the a feeler gauge to prove it... ;)
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Offline scottly

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Could this be another case of counterfeit NGK spark plugs?
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Offline CBJoe

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The plugs were new last year.

Whaddya guys think of this???

Did you Gap the plugs before you installed them?  It's hard to believe that you didn't notice that when you were changing them....

Joe
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Offline Lenny55

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Oh yeah, they were gapped correctly when I put them in last year.  I just wonder when between then and now that happened.  Like I said, the bike really runs pretty well for the most part, all four headers nice and hot.

Having said that though, I just finished replacing the plugs, caps, and wires.  Fired it up, and it wasn't revving all that well after a few seconds.  All the pipes seemed to be heating up the same, but then I noticed #4 was only warm.  Like it wasn't firing.

Anyway, it's dark here now, so I will have to troubleshoot tomorrow I guess.  Here's a pic of all four plugs if you're interested.  They look nice and tan at the tip.

'73 CB500

Offline Lenny55

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What would a worst case scenario be??
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Offline bucky katt

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i couldnt really tell from the pic, was there any actual physical damage on the ground electrode like maybe something colliding with that plug? do you have stock or high compression pistons?
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Offline Lenny55

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I wondered that as well Bucky, it looked like it had been bashed.  The more I look at it, the less it looks like that though.  It looks like the ceramic split and shrank almost.  At least I hope that's what it is, otherwise there's one hell of a big chunk(s) floating around there.  Cleaned the vacuum before I used it and checked it after, didn't see anything. 

The pistons are stock as far as I know.  The really old plug I took out last year didn't look damaged to the best of my knowledge.
'73 CB500

Offline scottly

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Could this be another case of counterfeit NGK spark plugs?
Bump. This subject of broken insulators came up a while back: someone posted a video from NGK, warning of counterfeit plugs, with clues on how to identify them...
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Offline Frostyboy

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I've pulled many s/plugs from car engines over the years & quite often found the ceramic insulator broken/missing with no ill effects to the engines.
In this case I'd suggest it was the piece of insulator that got on top of the piston & smashed into the earth electrode to close it up.
Hopefully it got pulverised the moment it got hit.
By all means, put the vac in there with a tube, but I reckon it'll fire up again without any drama.
Speaking of counterfeit s/plugs, have you seen this?
http://www.strangeamericans.com/images/content/159162/precision-spark-plug-manufacturing-in-china-pps-presentation.pps
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Offline Lenny55

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Thanks fellas, I can't open the link because I don't have office installed, it's asking me for the product key for the demo version I got with the pc.

I'm going to look into the conterfeit plug thing.  I got these from my local Kawa dealer, so it doesn't seem likely they would be.
'73 CB500

Offline scottly

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The link Frosty posted, although VERY revealing, wasn't the video I had seen posted before. Try going to NGK's website..??
Don't fix it if it ain't broke!
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Offline Old75_ratafe

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I would definatly check the engine the last time I saw a plug like that it was because the piston came up and slapped it.
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Offline 75cb550 (kyle)

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you should try to get/borrow a borescope... i wish i would have kept the one i had... very handy
« Last Edit: April 22, 2010, 08:32:23 AM by 75cb550 (kyle) »

Offline Gregorymoto

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Bummer, You should think about taking a Large Qtip (you might need to make your own) and cover the end with bearing grease. Don't leave gobs on it use just enough so that it will pick up any loose shards  in the chamber. Or take the thing apart.
Yep, i have issues with this sort of stuff.

Offline Lenny55

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A borescope would be handy for sure.  I forgot to mention that I was running the bike without the tank on it.  Could explain why #4 died I guess.  I need to mess with the fuel lines, and it was getting dark, so I just fired it up without the tank.

Was busy after work today and didn't get home til after dark, so I guess it'll be tomorrow before I even get to look at it. 

I bet it fires up on all four once the tank is back on and the lines are full.  At least I hope that's what happens. ::)

Q-tip and grease is a great idea as well.  A little late for me to try now though. 

Lenny.
'73 CB500