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Mar 7, 2010 | 10:45 PM

KYFATBOB

Thread Starter

Tourer

Joined: Jan 2010

Posts: 330

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From: Grayson Ky

What color is....

The end of your spark plug??? After doing the VH big radius 2 into 2 pipes, SE stage 1 air cleaner and stage 1 download the end of my plug is a grayish color... That tells me its lean, but I have no popping, cracking, backfire or nothing on deceleration... What I do have is improved throttle response and alot more low end torque... Do you think it is lean???????

Mar 7, 2010 | 10:52 PM

GREENOHAWK69

Grand HDF Member

Joined: Oct 2006

Posts: 3,663

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From: DFW

Quote:

Originally Posted by KYFATBOB

A lean condition typically has a WHITISH look to your spark plugs. A rich condition is typically BLACKISH. The sweet spot is typically TANISH in color.

There is something on this site pertaining to spark plug color, but you will have to search, I do not remember where it is located.

Mar 8, 2010 | 04:23 AM

jmpancoast

Outstanding HDF Member

Joined: Jan 2007

Posts: 3,438

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From: Chesterfield, VA

Here is a pretty good chart to help you read your plugs:

http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

Mar 8, 2010 | 04:53 AM

maddghost

Ultimate HDF Member

Joined: Apr 2008

Posts: 5,384

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From: Out on Deranged

Wow good chart JM! lots of choices there. A guy just has to hold his sparke plug next to his comp!

Mar 8, 2010 | 05:09 AM

jmpancoast

Outstanding HDF Member

Joined: Jan 2007

Posts: 3,438

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From: Chesterfield, VA

Quote:

Originally Posted by maddghost

Wow good chart JM! lots of choices there. A guy just has to hold his sparke plug next to his comp!

I have **** all over my computer screen from doing just that!

Mar 8, 2010 | 06:43 AM

dope_man_21

Ultimate HDF Member

Joined: Nov 2007

Posts: 6,799

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From: Carrollton, Georgia

Quote:

Originally Posted by jmpancoast

Here is a pretty good chart to help you read your plugs:

http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

I posted that same chart, way back when and had forgotten where it was, thanks. Someone should think about making that chart a sticky for all of the help it would be.

Mar 8, 2010 | 07:04 AM

rounder

Ultimate HDF Member

Joined: Oct 2007

Posts: 7,562

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From: Palm Harbor fl.

the spark plug does not tell your afr accurately. Especially if you just pulled the plug after just riding it. I can end up with the same looking plug when I richen my mixture or lean it out. To really know if you are lean, you need to have the bike exhaust metered on a dyno for AFR throughout the rpm range. About the only thing you can tell looking at a plug is if you are extremely lean or extremely rich and detonation. Plug won't really read differently if at 13.4:1 vs 14.7:1. you are factory set at 14.7:1 which is referred to as lean for our bikes, yet is supposed to be the ideal afr where all the fuel is burned in the combustion chamber. Most find our bikes perform best at about 13.4:1 or thereabouts.