Harley Davidson Forums

Engine Mechanical Topics Discussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.

Spark Plugs

Thread Tools
 
Search this Thread
 
Old Apr 6, 2017 | 02:25 PM
Share
  #1  
DieselDoc103's Avatar
DieselDoc103
Thread Starter
|
Tourer
Joined: Jul 2016
Posts: 253
Likes: 32
From: Cincinnati Ohio
Default Spark Plugs
Hey newb question here. ive noticed at Harley they sell ( screamin eagle spark plugs )

as far as a built engine goes id assume youd need a hotter plug but for a factory 103 with a stage 1 will a hotter plug benefit in anyway?

what are the screaming eagle plugs? its not like the MoCo is in the spark plug business.....
 
Reply
0
Old Apr 6, 2017 | 05:56 PM
Share
  #2  
Madduc's Avatar
Madduc
Advanced
Joined: Jun 2006
Posts: 98
Likes: 7
From: Dorr,MI
Default
At least in the car world when you build a car for increased HP, most times a cooler plug is used to help prevent pre-ignition. Just one step cooler, nothing drastic.
 
Reply
0
Old Apr 6, 2017 | 06:56 PM
Share
  #3  
Max Headflow's Avatar
Max Headflow
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,899
Likes: 8,006
From: poway
Default
Madduc is correct. On performance mods you typically go cooler. You typically need a compression increase to need to go cooler.. In the case of a stage 1, you can pull the plugs and look at them if you want. White is OK but bleached, eroded or gray ***** on the electrode are bad. Side strap should change color mid way.
 
Reply
0
Old Apr 6, 2017 | 09:07 PM
Share
  #4  
Ed Ramberger's Avatar
Ed Ramberger
Grand HDF Member
10 Year Member
Liked
Loved
Community Favorite
Joined: May 2015
Posts: 3,584
Likes: 1,213
From: Then Wisconsin, now North Carolina
Default
OE plug will be just fine
 
Reply
0
Old Apr 6, 2017 | 09:07 PM
Share
  #5  
TXCHOP's Avatar
TXCHOP
Road Master
Joined: Jan 2006
Posts: 1,221
Likes: 40
From: Chester NY
Default
Proper tune, stock plugs.
 
Reply
0
Old Apr 6, 2017 | 09:24 PM
Share
  #6  
Max Headflow's Avatar
Max Headflow
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,899
Likes: 8,006
From: poway
Default
Originally Posted by Max Headflow
Madduc is correct. On performance mods you typically go cooler. You typically need a compression increase to need to go cooler.. In the case of a stage 1, you can pull the plugs and look at them if you want. White is OK but bleached, eroded or gray ***** on the electrode are bad. Side strap should change color mid way.
I should have made my point more clear. Stage 1 is not a serious performance mod IMO.. Bump the CR to 10.5 to 1 and get the CCP over 200 and you might be looking for cooler plugs.

The rest was more about reading the plugs to see if you have an issue the current state of tune.
 
Reply
0
Old Apr 7, 2017 | 11:12 AM
Share
  #7  
FlaHeatWave's Avatar
FlaHeatWave
Road Captain
Joined: Jan 2014
Posts: 566
Likes: 70
From: The Redneck Riviera
Default
RA8HC Champion,,, The go-to Plugs for my guy that Owns / Operates a Tuning School...

$ave $$$ Champion makes Plugs for HD...
 
Reply
0

Trending Topics

Old Apr 7, 2017 | 04:24 PM
Share
  #8  
Max Headflow's Avatar
Max Headflow
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,899
Likes: 8,006
From: poway
Default
I use RA6HCs but then I don't own a stage 1.
 
Reply
0
HD Forum Stories

The Best of Harley-Davidson for Lifelong Riders

story-0

7 Times Harley-Davidson Chucked Tradition Out the Window

 Verdad Gallardo
story-1

7 Surprising Harley-Davidson Products that Are Not Motorcycles

 Verdad Gallardo
story-2

8 Best Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-3

10 Worst Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-4

Killer Custom's Jail Break Is The Breakout That Refused to Blend In

 Verdad Gallardo
story-5

Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

 Verdad Gallardo
story-6

Harley-Davidson Reveals Super Cool Cafe Racer Concept

 Verdad Gallardo
story-7

Engraved Rebellion: Inside Bundnerbike's Glam Rock II

 Verdad Gallardo
story-8

10 Motorcycles You Should Never Buy

 Joe Kucinski
story-9

10 Things Harley-Davidson Needs to Fix in 2026

 Verdad Gallardo
Old Apr 8, 2017 | 01:39 PM
Share
  #9  
Gozzie's Avatar
Gozzie
Road Captain
Joined: May 2008
Posts: 718
Likes: 152
From: Ozarks
Default
Do the RA8HC work with the knock detection ? If so I might switch over. I don't have a local shop to get the Harley plugs from.
 
Reply
0
Old Apr 8, 2017 | 08:50 PM
Share
  #10  
Sc0-'s Avatar
Sc0-
Road Captain
Joined: Oct 2012
Posts: 520
Likes: 37
From: houston, tx
Default
Just ordered some 10R12A, (32335-04), which are out if the VRod for a 107 10.8cr build
 
Reply
0



Advanced Search
Reply Closed Thread Share
Forum Jump

All times are GMT -5. The time now is 04:48 AM.

story-0
7 Times Harley-Davidson Chucked Tradition Out the Window

Slideshow: Harley-Davidson built its reputation on nostalgia, but every so often, the company took a hard left turn into the future.

By Verdad Gallardo | 2026-05-20 11:18:19


VIEW MORE
story-1
7 Surprising Harley-Davidson Products that Are Not Motorcycles

Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.

By Verdad Gallardo | 2026-04-29 16:50:35


VIEW MORE
story-2
8 Best Harley-Davidson Motorcycles Ever

Slideshow: Not every Harley gets it right, but these are the ones that genuinely earned their reputation.

By Pouria Savadkouei | 2026-04-15 14:23:21


VIEW MORE
story-3
10 Worst Harley-Davidson Motorcycles Ever

Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.

By Pouria Savadkouei | 2026-04-01 20:01:09


VIEW MORE
story-4
Killer Custom's Jail Break Is The Breakout That Refused to Blend In

Slideshow: Killer Custom's "Jail Breaker" build focuses more on stance and visual aggression than mechanical overhaul.

By Verdad Gallardo | 2026-03-18 19:20:32


VIEW MORE
story-5
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.

By Verdad Gallardo | 2026-03-07 16:15:30


VIEW MORE
story-6
Harley-Davidson Reveals Super Cool Cafe Racer Concept

Slideshow: Harley-Davidson's new RMCR concept revives the café racer formula with modern hardware-and it may be exactly the reset the company needs.

By Verdad Gallardo | 2026-03-04 12:23:37


VIEW MORE
story-7
Engraved Rebellion: Inside Bundnerbike's Glam Rock II

Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.

By Verdad Gallardo | 2026-02-24 18:19:44


VIEW MORE
story-8
10 Motorcycles You Should Never Buy

Slideshow: There is no shortage of great motorcycles to buy, but we would avoid these ten.

By Joe Kucinski | 2026-02-19 14:50:51


VIEW MORE
story-9
10 Things Harley-Davidson Needs to Fix in 2026

Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.

By Verdad Gallardo | 2026-01-13 18:33:17


VIEW MORE