Broken spark plug

DraginMiFeet

DraginMiFeet

Well-known member
Well I did the inevitable, I broke a spark plug on my 05 Harley ultra classic. just below the head. Im probably going to have to have the head removed in case part of the plug fell into the cylinder. Ill get it towed to the Harley Dealer unless someone has a better solution? has anyone had this happen to them and what will be the cost of fixing this. thanks.
 
crankcall said:
how'd you manage to do that?
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I've seen it from the spark plug getting seized in the block (aluminum vs. steel = corrosion) so when you try and take it out it breaks the threaded portion off inside the block :(

After I saw that, I always anti-seize (the copper stuff) my spark plugs.

-Jamie M.
 
use an easy out insert tool with an extention. when you get it out, use a magnet inside the hole to fish out any savings. turn the engine over with the starter, with the plug out. that will blow out anything else, and away you go.
 
crankcall: it's exactly how toysareforboys said it. I would guess it's from not properly winterizing ... taking the plugs out and coating the inside of the cylinders with oil then turning it over a few times to coat everything. This was my first winter with this bike and I didn't do it. I would guess that the previous owners didn't either as it's only got 7,000 miles on it and was in storage for a number of years. I was slowly replacing all the consumable parts as everything was as the day it was bought.

Thanks Stewart.. I have a feeling that the threads on the block might have been compromised, there were some metals pieces on the thread of the part that broke off. Think i'll go cry now.
 
DraginMiFeet said:
crankcall: it's exactly how toysareforboys said it. I would guess it's from not properly winterizing ... taking the plugs out and coating the inside of the cylinders with oil then turning it over a few times to coat everything. This was my first winter with this bike and I didn't do it. I would guess that the previous owners didn't either as it's only got 7,000 miles on it and was in storage for a number of years. I was slowly replacing all the consumable parts as everything was as the day it was bought.

Thanks Stewart.. I have a feeling that the threads on the block might have been compromised, there were some metals pieces on the thread of the part that broke off. Think i'll go cry now.
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Not necessarily the end of the world, as stated above you may be able to withdraw the electrode with a damaged bolt extractor. Filings will most likely come from the plug threads and be withdrawn with the electrode, so if you're careful to blow the area out as you withdraw the busted plug you'll probably avoid anything falling in to the cylinder. I would avoid turning the engine over with the starter until you've blown the cylinder out though, if anything does manage to get down there you run the risk of scoring the cylinders using the starter... try creating a vacuum through the plug port and turning the rear wheel slowly by hand with the bike in top gear, this will move the pistons slightly and dislodge anything that may have fallen in.

Good luck.

p.s. get yourself some coppaslip for the plug threads to avoid this happening again...
 
How accessible is the spark plug hole? If its easily reached...you might be able to get the old plug out and (depending on the threads) use a thread chaser or thread insert.

Head removal = $$$

The other way...its a lot of time and patience...but its more affordable.
 
Thanks for everyone's input. I don't want to make a bad situation worse so I've decided to let the dealer do this one. I'm getting it towed to Davies Harley Davidson in Richmond Hill tomorrow. Thanks CAA.

And thanks for the Anti-Seize reco..
Canadian Tire $15.99

  • For easy assembly and disassembly of metal parts

  • Prevents galling during assembly
  • Contains a high percentage of micro-fine copper flakes in a semi-synthetic grease carrier to prevent seizing
  • Electronically conductive, can be used on ground bolts and sensors
  • Inhibits rusting, cold welding and galvanic corrosion between assembled parts
  • Effective at high temperatures up to 982°C (1800° F)

  • Ideal applications include: spark plug threads in aluminum blocks, exhaust manifold bolts, engine bolts, oxygen sensor, knock sensor, thermostat housing bolts, fuel filter fitting and battery cable connections

  • 227g brush-top can
 
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They were/are Harley Davidson spark plugs. Exact same as the replacements I bought. I think the plugs were the original when the bike was built 8 years ago as it was in storage by previous owner for a number of years but was ridden for the last couple of years with very low mileage. It has 7,000 miles on it right now. I bought the bike last fall.
 
toysareforboys said:
So don't be dumb and over torque them? lol.

-Jamie M.
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The thing with torque, and the point of that tech bulletin is that most of the force (torque) is friction between the mating surfaces on the thread and the gasket faces. If you reduce the friction by applying anti-seize it is quite possible to over tighten to the point of breaking the plug even when using an accurate torque wrench. Under normal circumstances better than 90% of the torque is used to overcome friction, the rest is used to stretch the bolt the correct amount.
 
good point Tripletrouble. I had the dealer deal with the siezed/broken plug. They charged me $92 and put 2 new plugs in. CAA towed it into the dealer.
 
Jampy00 said:
Very good info !!
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+1 learned something valuable today, gonna check NGK packaging to see if there is any warning because there should be.

DraginMiFeet said:
good point Tripletrouble. I had the dealer deal with the siezed/broken plug. They charged me $92 and put 2 new plugs in. CAA towed it into the dealer.
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wow, that worked out pretty good
 
I think it's worth noting that anti-seize be avoided on initial installation but since it comes off at removal anti-seize be used if reusing same plug. That's what I got from the blurb. Sound correct?
 
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