Spark Plug Service Interval
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Joined: Dec 2017
Posts: 96
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From: Brisbane, Australia
Spark Plug Service Interval
HD specify replacement of the spark plugs every two years or every 30000mi, whichever comes first. Its the first time Ive ever come across a time based replacement for spark plugs and the very short two year time interval seems ridiculous. Does anyone know is there a valid basis for such frequent changing of the spark plugs?
Eg. I had a few BMWs which call up spark plug replacement at 25000mi, no time replacement specified.
Eg. I had a few BMWs which call up spark plug replacement at 25000mi, no time replacement specified.
HDF Community Team
Joined: Sep 2013
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From: Wisconsin
HD specify replacement of the spark plugs every two years or every 30000mi, whichever comes first. Its the first time Ive ever come across a time based replacement for spark plugs and the very short two year time interval seems ridiculous. Does anyone know is there a valid basis for such frequent changing of the spark plugs?
Road Warrior
Joined: Jul 2014
Posts: 1,584
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From: VA
HD specify replacement of the spark plugs every two years or every 30000mi, whichever comes first. Its the first time Ive ever come across a time based replacement for spark plugs and the very short two year time interval seems ridiculous. Does anyone know is there a valid basis for such frequent changing of the spark plugs?
Eg. I had a few BMWs which call up spark plug replacement at 25000mi, no time replacement specified.
Eg. I had a few BMWs which call up spark plug replacement at 25000mi, no time replacement specified.
HDF Community Team
Joined: Mar 2017
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From: Texas
I am loyal to the service manual, so I changed them out at 2 years/18k miles. They looked horrific on the outside (lots of corrosion), but the threads and, more importantly, the electrode still looked okay. The corrosion is from riding in the rain and washing the bike - the top spark plugs sit down in a cavity that doesn't drain, so you have to boil the water out of there or it'll just sit in there until it evaporates on its own. The plugs could have gone on many more miles - it's not like sitting around doing nothing damages a spark plug. They were a whopping $15 for the set so I didn't even hesitate.
Seasoned HDF Member
Joined: Jun 2010
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From: Upstate New York
That would work, but having to pull the gas tank to change the spark plugs still sucks.
HDF Community Team
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From: Texas
A couple bolts and two plugs is a piece of cake.
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Seasoned HDF Member
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From: Pennsylvania
If the motorcycle is running okay performance wise and still getting the same MPG, I'll leave them in. I have a 2002 Toyota Avalon that had 275,000 miles with the orginial spark plugs. Had them changed out only because I had the intake manifold off replacing the valve cover gaskets. Plugs still looked good.
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Joined: Dec 2017
Posts: 96
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From: Brisbane, Australia
Thanks! it has reaffirmed my thinking, there seems no strong case for such frequent replacement. BUT Ill inspect them as part of my annual servicing to be sure, and make a call over time. I share myself across 4 bikes for recreation riding only and have only done 5000mi in 2y on my FLDE, so it seemed overkill to just change them regardless at this point. I have a 40y engineering background (electrical) and am very particular about preventative maintenance, logbook servicing all my bikes annually, but this just didnt make sense! I will report back if a change seemed necessary.
Btw, have only just changed the spark plugs this year on a 13yo BMW R1200 I own (also twin spark), as its 25000mi spark plug replacement recommendation came up with its annual service. Was still running perfectly BUT admittedly the plugs were showing the need for replacement. Also have a 15yo BMW R1200 (also twin spark) with the same plugs it left the Berlin factory with, but again still short of the 25000mi replacement recommendation ... running fine and plugs still looking good. Cheers!
Btw, have only just changed the spark plugs this year on a 13yo BMW R1200 I own (also twin spark), as its 25000mi spark plug replacement recommendation came up with its annual service. Was still running perfectly BUT admittedly the plugs were showing the need for replacement. Also have a 15yo BMW R1200 (also twin spark) with the same plugs it left the Berlin factory with, but again still short of the 25000mi replacement recommendation ... running fine and plugs still looking good. Cheers!
HDF Community Team
Joined: Mar 2017
Posts: 7,860
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From: Texas
Like I just told the car dealership tonight when they performed an oil change and multipoint inspection:
“Sir, we found your cabin air filter is dirty, did you want us to replace it?”
”How much does it cost?”
”$14.99 plus installation and tax”
”Bullshit, you’re not going to charge me installation when I’ve already paid you to remove the filter, check it, and reinstall it.”
”Wow, never thought of it that way. I’ll have the technician put a new one in without the installation charge.”
Moral: If you’re going to spend the 20 or so minutes to check the spark plugs, just replace them for the $15 it’ll cost.
“Sir, we found your cabin air filter is dirty, did you want us to replace it?”
”How much does it cost?”
”$14.99 plus installation and tax”
”Bullshit, you’re not going to charge me installation when I’ve already paid you to remove the filter, check it, and reinstall it.”
”Wow, never thought of it that way. I’ll have the technician put a new one in without the installation charge.”
Moral: If you’re going to spend the 20 or so minutes to check the spark plugs, just replace them for the $15 it’ll cost.
