plug recommendations?
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Road Warrior
Joined: Aug 2014
Posts: 1,612
Likes: 32
From: usa
plug recommendations?
I have 04 heritage.
1550 cc
10.5 :1 dome pistons
racing heads iirc
s&s gear cam
Looking for upgrade for plugs..
I did look around a bit, still need someone who knows what he's doing
Thx
If i should post on different board, say which
1550 cc
10.5 :1 dome pistons
racing heads iirc
s&s gear cam
Looking for upgrade for plugs..
I did look around a bit, still need someone who knows what he's doing
Thx
If i should post on different board, say which
Supporter
Joined: Jan 2007
Posts: 15,787
Likes: 5,612
From: along the shore of Mishigami
My had an indy shop put non-HD plugs in the Ultra Classic he has and on his trip from FL to NY started tripping codes. We put stock in the bike while he was here no codes on the way back to FL.
Road Warrior
Joined: May 2012
Posts: 1,956
Likes: 75
From: CA
Keep in mind the following when looking at aftermarket plugs:
Originally Posted by lightweight bob
1) Your spark plug choice is fine for Sportsters but not for HD's with "ion sensing
knock detection" as in most Harley's. That system requires a plug with 20k ohms
resistance to function properly and most aftermarket plugs are 6k ohms.
2) Manufactures of iridium plugs caution against using the gapping tool you show
for fear of damaging the thin center electrode. The old tool that just bends the
ground electrode is specified.
BTW - do you ever index your plugs? I never did until one day I pulled one that
had the ground electrode exactly between the intake valve ane the center
positive electrode - it had begun to carbon track opposite the ground electrode.
FWIW - In my '06 SG I use standard Champion #810 / RA8HC at $1.55 each. They
are 20k ohms resistance - no surprise as they make them for MOCO.
Bob G
1) Your spark plug choice is fine for Sportsters but not for HD's with "ion sensing
knock detection" as in most Harley's. That system requires a plug with 20k ohms
resistance to function properly and most aftermarket plugs are 6k ohms.
2) Manufactures of iridium plugs caution against using the gapping tool you show
for fear of damaging the thin center electrode. The old tool that just bends the
ground electrode is specified.
BTW - do you ever index your plugs? I never did until one day I pulled one that
had the ground electrode exactly between the intake valve ane the center
positive electrode - it had begun to carbon track opposite the ground electrode.
FWIW - In my '06 SG I use standard Champion #810 / RA8HC at $1.55 each. They
are 20k ohms resistance - no surprise as they make them for MOCO.
Bob G
Last edited by _Gir_; Jun 25, 2016 at 01:08 AM.
Outstanding HDF Member
Joined: May 2013
Posts: 3,427
Likes: 164
From: Home
A couple of things to help you understand what you are asking:
http://www.spridgetguru.com/TA0061.html
http://www.spridgetguru.com/TA0061.html
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Club Member
Joined: May 2007
Posts: 145,895
Likes: 821
From: 40 miles Northeast of Indy..
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I've read many post in here over the yrs that some others have tried to improve the plugs,, only to get a worse result than what the OEM plug do..
If anything you might go with some SE plug wires..
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Stellar HDF Member
Joined: Apr 2009
Posts: 3,039
Likes: 11
From: Northern Ontario
I was having plug issues with my FLH high compression engine, tried champs , ngk autolites then went back to the AC Delcos that previous owner/builder used since new and 5000 km + later havent had an issue again .
AC Delco R121XLS
AC Delco R121XLS
Stellar HDF Member
Joined: Feb 2010
Posts: 3,386
Likes: 255
From: Southern California
As long as the Spark Plugs are recommended (in their Catalog) by a well known Maufacturer of the Spark Plug, you'll do just fine. Champion, ACDelco, NGK, Denso, Bosch, etc. I am NOT a fan of "Gimmick" Spark Plugs such as Split Fire, Rapid Fire, etc Iridium or Platinum will do no harm, but their advantage is in their extened life. With Platinum electrodes (both electrodes and not buttons welded onto the electrodes) anti-fouling charecteristics can be helpful. But this is only true if fouling is a problem now. Niether provides any performance gain. In any case, it's debatable whether or not their addition life span will justify their additional cost, particularly on a Harley, where the Spark Plugs are so easy to get to and most owners are unlikely to keep a set of Spark Plugs for the ~100,000 miles that they will last for. Be aware that there is more Mouse Milk and full on 100% Marketing BS surronding Spark Plugs than one might ever imagine.