Simple Spark Plug Question
Road Master
Joined: Nov 2010
Posts: 901
Likes: 5
From: Springfield, MO
You'll know if the bike's anti-knock system is malfunctioning due to the aftermarket plugs... it will turn on the check engine light and throw a code in that case.
Having said that... why chance it? Buy the plug that is manufactured to operate in the ohm range the anti-knock system is looking for. That would be the OEM spark plug.
Having said that... why chance it? Buy the plug that is manufactured to operate in the ohm range the anti-knock system is looking for. That would be the OEM spark plug.
Tourer
Joined: Dec 2008
Posts: 272
Likes: 74
From: Stowe Pa
Simple answer: 2005 and later Harley-Davidson EFI systems incorporate an "Anti-knock" feature that operates by reading the current resistance through the spark plugs.
The use of any other spark plug other than 'Stock' (6R12) disables the anti-knock feature.
Source: https://www.hdforums.com/forum/fuel-...ml#post9359708
Your call
The use of any other spark plug other than 'Stock' (6R12) disables the anti-knock feature.
Source: https://www.hdforums.com/forum/fuel-...ml#post9359708
Your call
Outstanding HDF Member
Joined: Jan 2011
Posts: 2,590
Likes: 31
From: Western Illinois, land of bad roads, and corrupt politicians
You've never heard of FuelMoto? Look at the second post on that link and you will see that it's not one of those "read it on the internet" things. My PowerVision even has a section to turn anti-knock on and off.
Last edited by shooter5074; Apr 14, 2015 at 05:54 PM.
Road Master
Joined: Mar 2006
Posts: 791
Likes: 0
From: Arizona
I just bought a set of NGK Iridium plugs and damn, they are nice! I've been using the regular NGK for a long time with no issues, but these iridium plugs are something else! Hardly any pings and the engine runs smoother too!
Ultimate HDF Member
Joined: Jan 2008
Posts: 6,532
Likes: 132
From: SoCal
It is just FM being careful, nowhere do they say use of non-HD spark plugs will disable the ion-sensing feature. And the sepst and tts has the feature to disable, you tune with the feature off then after you are done tuning you turn it back on. At least that how I was told it should be done. You don't want the ecm to retard if you can help it.
Tourer
Joined: Dec 2008
Posts: 272
Likes: 74
From: Stowe Pa
http://harleytechtalk.org/htt/index....c,41271.0.html
Ultimate HDF Member
Joined: Jan 2008
Posts: 6,532
Likes: 132
From: SoCal
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Outstanding HDF Member
Joined: Jan 2011
Posts: 2,590
Likes: 31
From: Western Illinois, land of bad roads, and corrupt politicians
It is just FM being careful, nowhere do they say use of non-HD spark plugs will disable the ion-sensing feature. And the sepst and tts has the feature to disable, you tune with the feature off then after you are done tuning you turn it back on. At least that how I was told it should be done. You don't want the ecm to retard if you can help it.
I don't think it's a matter of them being careful. There are some plugs that do disable anti-knock. Don't know which off hand. There are so many brands of plugs that they can't research each and every one to be sure they have the resistance needed.
And it's one of those situations where..... plugs are cheap. Why save a buck or two, when you don't have to change them that often. It's like those guys who hunt for O rings from other vendors to save a few cents, rather than just grab a few at the dealer.
If they are so anti-dealer, and anti-Harley, maybe they would be happier with a metric, or a Polaris product.
Last edited by shooter5074; Apr 14, 2015 at 06:55 PM.
Ultimate HDF Member
Joined: Jan 2008
Posts: 6,532
Likes: 132
From: SoCal
I don't think it's a matter of them being careful. There are some plugs that do disable anti-knock. Don't know which off hand. There are so many brands of plugs that they can't research each and every one to be sure they have the resistance needed.
And it's one of those situations where..... plugs are cheap. Why save a buck or two, when you don't have to change them that often. It's like those guys who hunt for O rings from other vendors to save a few cents, rather than just grab a few at the dealer.
If they are so anti-dealer, and anti-Harley, maybe they would be happier with a metric, or a Polaris product....... I think I just thew up in my mouth a little.
And it's one of those situations where..... plugs are cheap. Why save a buck or two, when you don't have to change them that often. It's like those guys who hunt for O rings from other vendors to save a few cents, rather than just grab a few at the dealer.
If they are so anti-dealer, and anti-Harley, maybe they would be happier with a metric, or a Polaris product....... I think I just thew up in my mouth a little.