Spark Plug - Potential issues

Boris

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Dec 21, 2013
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midlands. UK
I’m aware that this matter has been raised numerous time on this forum, however I’m highlighting again, as it may help avoid a future similar problem that of one of our fellow Super Tenere owners is currently facing.

I changed my plugs a while back and all 4 that I took out showed no sign whatsoever of water ingress on the coil or plugs. Last winter and about 8-9k miles later I checked the same plugs and still no sign of any water ingress.

So far this riding season I’ve done about 6k miles, some of it through some quite heavy and prolonged rain. Over the past few startups, the bike has been a little lazy to fire up, not battery lazy, just fire up lazy. I decided to do a tank up, air filter, plug and general check to see if there’s anything amiss.

Air filter filthy (about 8k miles) so that’ll be changed, more worrying though are the state of plugs 1&2 (left to right sat on the bike), which along with the coils, showing significant signs of water ingress, also with the early signs of discolouration where the porcelain meets the hex. All came out easy enough and have been changed. I’ve also siliconed the coil cap where it meets the top of the plug well. Plugs/coils 3&4 showed no sign of water ingress.

Note - my bike is garaged when not in use.

75611D54-0187-4D9E-86FB-74E5FB208557.jpeg
 

Nikolajsen

"Keep it simple"
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Jul 1, 2017
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Denmark
So after +9000 miles, they suddenly starts looking like that?
:eek::oops:
Maybe the heavy and long rain, make the area around these plugs, so cold that the water around the plugs don't evaporates, when stopping.
Opposite if it only were a short downpour...I don't know...but strange
 

Boris

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Dec 21, 2013
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midlands. UK
No, that was after 6k miles which included lots of rain (Scotland). At 8-9k miles after almost all dry riding (last summer) they still looked like new.

It’s rust where water must be getting in on the left cylinder plug wells. The right 2 plugs still looked like new, no sign whatsoever of water getting past the coil caps.
 

WJBertrand

Ventura Highway
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Jun 20, 2015
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Ventura, CA
I kinda doubt much water can get it there and stay when the engine is hot. What I do wonder about is water finding its way in there when the bike is parked in the rain with a cold engine. The fact that the two most leftward plugs showed this condition could be because they are situated downward when the bike is parked on the side stand?
 

tntmo

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Nov 10, 2017
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649
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San Diego, CA
The front tire spews water up on top of the engine. If you ride through heavy rain long enough, it will also swamp out the air box. I found this out after riding in torrential rain in Canada for two days straight.
 

Boris

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Dec 21, 2013
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midlands. UK
I kinda doubt much water can get it there and stay when the engine is hot. What I do wonder about is water finding its way in there when the bike is parked in the rain with a cold engine. The fact that the two most leftward plugs showed this condition could be because they are situated downward when the bike is parked on the side stand?
This is pretty much my thoughts too, however when I’m on a tour/trip and the bike is left outside, I almost always park it on the main stand. Logic does suggest you’re right though.
 

RCinNC

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Aug 30, 2014
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2,816
Location
North Carolina
I spread a layer of copper anti-seize on the hex portion of the plug to provide a barrier against corrosion. I used it mostly because it was handy, and had a temperature rating of -30 degrees F to almost a thousand degrees.

I don't think they want you to use anti-seize on the threads because it reduces friction, so if you use a torque wrench to install the plugs and don't compensate for the lesser friction, your torque settings will be too high and you risk breaking off the plug.
 
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