I would like to better understand the relationship between the width of the mixture ring and the color of the plug insulator. As I understand it, the mixture ring width is a direct function of jetting, mostly the main and to some extent needle taper. Conversely, the insulator color is mostly affected by the heat range of the plug and operating conditions. Is this right?
As an example, from plug chops I'm getting a mixture ring about 0.030" wide at the bottom of the insulator. The transition from the ring to the insulator is very crisp, less than 0.010" wide. The remainder of the insulator is predominantly white, with some very light coffee colorings. Does this indicate that the jetting is just about right, but the plug is borderline hot for this application?
In reality, I spend very little time pinned WFO in 5th, so I wouldn't think I should go with a cooler plug. Under normal trail riding, when I pull a plug after a ride, the insulator is an even caramel color. So that would indicate the heat range is appropriate for my typical riding conditions.
Just hoping to clarify this distinction.:think:
As an example, from plug chops I'm getting a mixture ring about 0.030" wide at the bottom of the insulator. The transition from the ring to the insulator is very crisp, less than 0.010" wide. The remainder of the insulator is predominantly white, with some very light coffee colorings. Does this indicate that the jetting is just about right, but the plug is borderline hot for this application?
In reality, I spend very little time pinned WFO in 5th, so I wouldn't think I should go with a cooler plug. Under normal trail riding, when I pull a plug after a ride, the insulator is an even caramel color. So that would indicate the heat range is appropriate for my typical riding conditions.
Just hoping to clarify this distinction.:think: