Simple Spark Plug Question
Road Warrior
Joined: Aug 2009
Posts: 1,630
Likes: 17
From: Central FL
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
Extreme HDF Member
Joined: Dec 2007
Posts: 13,402
Likes: 941
From: Illinois
Any plug meeting the specs of the HD plug in heat range and resistance will work fine. It only needs to be a resistor plug with 6 ohms resistance.
I use the NKG iridium plug from J&P. They preserve the anti Knock system and work better than the stock HD plug in all aspects.
I use the NKG iridium plug from J&P. They preserve the anti Knock system and work better than the stock HD plug in all aspects.
Seasoned HDF Member
Joined: Sep 2009
Posts: 17,151
Likes: 6,175
From: SE Michigan
Any plug meeting the specs of the HD plug in heat range and resistance will work fine. It only needs to be a resistor plug with 6 ohms resistance.
I use the NKG iridium plug from J&P. They preserve the anti Knock system and work better than the stock HD plug in all aspects.
I use the NKG iridium plug from J&P. They preserve the anti Knock system and work better than the stock HD plug in all aspects.
Its hard enought to feel the ~~ 10% difference you get from a Stage 1, let alone a very slight marginal difference with plugs (even wonder if the difference would be measurable)
Outstanding HDF Member
Joined: Jan 2011
Posts: 2,590
Likes: 31
From: Western Illinois, land of bad roads, and corrupt politicians
Argue with these guys https://www.hdforums.com/forum/fuel-...ml#post9372265 I trust their knowledge, more than someone from the internet.
Ultimate HDF Member
Joined: Jan 2008
Posts: 6,532
Likes: 132
From: SoCal
No need to, I have experienced what works. Funny you refer to some guy on the internet as not knowing but refer to a thread on the internet as the truth, LOL Where did you become acquainted with FM? On the internet is my guess
Outstanding HDF Member
Joined: Jan 2011
Posts: 2,590
Likes: 31
From: Western Illinois, land of bad roads, and corrupt politicians
No....... I'm a customer. I was refereed to them by a friend. I've been to their place of business. I've met them in person. They are a half days ride from where I live.
Nice try though..... thanks for playing.
Ultimate HDF Member
Joined: Jan 2008
Posts: 6,532
Likes: 132
From: SoCal
You crack me up, LOL
Road Warrior
Joined: Aug 2009
Posts: 1,630
Likes: 17
From: Central FL
Argue with these guys https://www.hdforums.com/forum/fuel-...ml#post9372265 I trust their knowledge, more than someone from the internet.
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Outstanding HDF Member
Joined: Jan 2011
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From: Western Illinois, land of bad roads, and corrupt politicians
They are the go to guys for tuners, maps, intake and exhaust. They are also a forum sponsor. http://www.fuelmotousa.com/