bigboreCR

Member
Nov 8, 2001
8
0
I did some jetting changes and my bike runs great but no matter how i ride it, i keep getting the same plug reading it is black on one side of the insulator and white on the other ,down the middle split in half is this normal or is there something wrong.thanks.
 

Rich Rohrich

Moderator / BioHazard
LIFETIME SPONSOR
Jul 27, 1999
22,838
16,902
Chicago
What type of riding are you doing before you try to "read" the plug?
 

skhasky

Member
Apr 8, 2002
136
0
Sounds like it is running really lean on top - which is making the plug white. When you chop the throttle, the pilot circuit is extremely rich which plackens the part exposed to the brunt of the intake mixture. A guess... for what it is worth...
 

bigboreCR

Member
Nov 8, 2001
8
0
i ve done a full throttle chop and a half throttle chop,the jetting changes i did was move the jet needle clip up one to lean the mid a little, before i did this i had alot of spooge and the plug was completly black.
 

bigred455

"LET'S JUST RIDE"
LIFETIME SPONSOR
Sep 12, 2000
782
0
You will not get a reading on a new plug on the insulator nose no matter how big your main is.It will show white doing a wide open throttle check.I like to use a slightly used plug.
 

Jaybird

Apprentice Goon
LIFETIME SPONSOR
Mar 16, 2001
6,452
0
Charlestown, IN
I tend to disagree with those statements, bigred455.
 

skhasky

Member
Apr 8, 2002
136
0
I like feel too - however, I check the plug and I would be curious as to why a plug would be half-and-half! New plugs... if you are close they tend to saty white, but if you are way rich - they will show color after a minute, so to that end they can be of value.
 

Jaybird

Apprentice Goon
LIFETIME SPONSOR
Mar 16, 2001
6,452
0
Charlestown, IN
That new plug should show burn way down at the shank, even jetted close, yes?
I keep my sx tuned pretty well and I like to make changes when warranted even if I'm just playing. I do notice that this particualr motor tends to have a burn spot on one small part of the insulator. I attribute this to turbulence during the burn. Can't really consider it a half-n-half thing though.
The feel method has to be the best one because it is ultimately what you are after anywho. I've always thought that when I look at the plug, if I have a nice tan insulator, a burn ring close to the bottom of the insulator, and a destinctive break on the strap then I'm pretty close...as long as the ride pans out.
 

bigred455

"LET'S JUST RIDE"
LIFETIME SPONSOR
Sep 12, 2000
782
0
Originally posted by Jaybird
I tend to disagree with those statements, bigred455.
..

I have done this many of times installed a new plug did a throttle chop,and the plug has it original color. I wen't up to a 180 main from a 160 just to see,guess what no color, i knew the 160 is what the bike wanted i was just testing. If i have a slightly used plug with color on the insulator nose not the shank and i go up 1 step on the main i can get a change in the plug color,compared to a new plug.Remember i am talking about the nose of the plug not the shank.It sounds to me big bore cr is looking at the nose of the insulator not the shank,so i still believe my statement.
 

Jaybird

Apprentice Goon
LIFETIME SPONSOR
Mar 16, 2001
6,452
0
Charlestown, IN
From what jetting you can do from plug color, it makes not a wit of difference if its a new or old plug, except that with a new plug there is no former residue to burn off.
Maybe I'm missing something that you "dont use a new plug" guys know.
Fill me in please. Perhaps a bit more than "I put in a fatter main and guess what, no color change". Unitl I can be convinced with a little more than unsupported anecdotal data, I contend a new plug is best for tunning.
 

bigred455

"LET'S JUST RIDE"
LIFETIME SPONSOR
Sep 12, 2000
782
0
What i am saying is i find it very difficult to check your main by the plug color of a brand new plug on the insulator tip.I go by feel,I was trying to explain that, what i hear so often '' my plug is white i must be lean" I am saying it takes a while for the insulator tip to show color on a new plug.
 

Rich Rohrich

Moderator / BioHazard
LIFETIME SPONSOR
Jul 27, 1999
22,838
16,902
Chicago
Originally posted by bigred455
What i am saying is i find it very difficult to check your main by the plug color of a brand new plug on the insulator tip.

That's because you can't read the main jet strength on the nose of the insulator. All you are really reading there is plug temperature. You need to run a new plug to properly read the main, and you need to look deeper than the insulator nose to get the information you are looking for.
 


Top Bottom