Changed plugs now runs like crap

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Aug 15, 2011 | 08:05 PM

Herksuper

Thread Starter

Tourer

Joined: Aug 2011

Posts: 321

Likes: 2

From: Spring Lake

Changed plugs now runs like crap

Soooo, I decided to throw in some Iridium plugs since they needed changed out anyway. She's a 2009 Heritage Softail Classic w/ 18,000+ miles. Put in the new plugs and runs like crap gapped at .40. I know the tolerance is .038 - .043...would changing the gap make a difference? I'm about to throw in my old plugs to have it run right. It idles like crap and pops like it's lean with the new plugs.

Aug 15, 2011 | 08:15 PM

dennyo

Seasoned HDF Member

Joined: Dec 2008

Posts: 19,745

Likes: 1,183

From: Jamestown, CA

I just Run the Stock Plugs , I tried-um all , Stock plugs run cooler too
I gap-um at 40 also , Put your old plugs back in and see if that fix it ,, Good Luck

Aug 15, 2011 | 09:48 PM

2008crossbones

Road Captain

Joined: Apr 2011

Posts: 645

Likes: 1

From: manchester NH

your not supposed to gap iridium or platinum plugs.... you prob broke them,, just get the platinum harley plugs,, they are like 15 bucks for the set,, throw them win and call it a day...

Aug 15, 2011 | 10:02 PM

TattedUp

Tourer

Joined: Sep 2009

Posts: 427

Likes: 0

From: Louisiana

Also check the porcelain on the plug if they've been dropped before it could be cracked and would make it not fire right.

Aug 15, 2011 | 11:51 PM

av8or

Road Master

Joined: Jul 2009

Posts: 1,052

Likes: 12

I have heard that they (the Iridium) can throw a code due to a different amount of current draw to fire the plug. It has to due with the adaptive knock control. I use the cheap ($1.77) plugs from Shcucks, and they work fine.

Aug 16, 2011 | 01:20 AM

oct1949

Club Member

Joined: May 2007

Posts: 145,895

Likes: 821

From: 40 miles Northeast of Indy..

Read this and U'll know why I still use the same plugs that came from the factory..

Make sure U read what it says at the bottom of the page at least.

http://www.harleyhelp.com/sparkplg.html

Aug 16, 2011 | 01:26 AM

BlockHead96

Outstanding HDF Member

Joined: May 2008

Posts: 2,923

Likes: 13

From: Asscrackistan

Quote:

Originally Posted by 2008crossbones

your not supposed to gap iridium or platinum plugs.... you prob broke them,, just get the platinum harley plugs,, they are like 15 bucks for the set,, throw them win and call it a day...

Never heard that one before. I gaped mine when I ran them and they were just fine, the bike idled even better and seemed to start quicker. I do run stockers from J&P, OEM HD and much cheaper than the stealer.

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Aug 16, 2011 | 05:57 AM

LarryLives

Road Warrior

Joined: May 2011

Posts: 1,396

Likes: 7

From: Connecticut :(

As 2008crossbones said, I agree....
I was running pipes a while back without ac or tune, had a ton of pop at decel.
Swapped to the HD Screamin Eagle plat lugs (the ones for stock compression), and a set of SE wires.
Popin went away!
Great set up!
and cheap imo...
19.99 for wire set and 14.99 for a set of plugs.