View Full Version : Please help me to identify my spark plug color


vmax
March 28th, 2014, 01:30 AM
Hi all,

Can somebody help me to identify my sparkplug color. I just replace my stock exhaust with slip on and shim each stock needles with 1 washer 0.53mm . Then I adjust mixture screw L 2.75 and R 2.25. Also replace stock filter with knn drop in. PJ and MJ All stock. Should I need add more washer or just turn the mixture screw?

Ps : spark plug color with full turn black is the right side.

Appreciate you comment my jetting situation.

quarterliter
March 28th, 2014, 08:40 AM
Why do you have the mixture screws different on the two carbs?

Racer x
March 28th, 2014, 11:46 AM
I would say you are lean. Stock is 98 so to to 100. Its not unusual to have the idle screws set different. But they should be set to balance the carbs at idle. Not just randomly put in a position.
Also you should start with new plugs for tuning.
They look lean because the porcelain is white and should be a light tan color. And the left one looks like the tip is starting to melt. Are there any little black dots on the white part? I can't tell for sure.
Also when you look deep down the porcelain. There should be a different color about half way down. This will tell you if you have the proper heat range.

fast1075
March 28th, 2014, 01:27 PM
I would ask if the plugs are the proper heat range, and properly installed first of all. Racer X has a good question about specks on the insulator. Additives in the fuel form tiny specks when the combustion gas gets too hot, soon after toy start melting vital parts.

I don't trust the quality of my monitor to view the color as it actually is. If the side electrodes are completely clean and blue, you need more fuel.

The "smoke ring" Racer X is referring to should be distinct and a few mm up from the base of the ceramic.

Tan coloring doesn't make the most power, but it does mean "safe". My mentors in dragracing also taught me to take a close look at the piston dome color, but that requires a good borescope. You can get a plug viewer from any speed shop, but a lighted magnifying glass will do in a pinch.

dcj13
March 28th, 2014, 02:11 PM
Is it me? The porcelain insulators look clean/new. Maybe my vision is going bad. And, yeah, i notice the black stuff on the end of the shell...

It would be more telling if the shots of the plug were taken at an angle so we could see the electrode (side and top) and the ground electrode, as well as a bit of the side of the insulator (show a bit of leg, if you would).

Motofool
March 28th, 2014, 03:48 PM
........Can somebody help me to identify my sparkplug color..................

Those are way too virgin.

In order to obtain an accurate reading, you need to give those plugs some extended work and high operational temperature, especially at sustained high speeds (avoid city traffic and frequent stops-goes).

Then, use this reference:
http://www.dansmc.com/sparkplugs1.htm

http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

vmax
March 28th, 2014, 07:33 PM
Why do you have the mixture screws different on the two carbs?

Cause stock needles different length.