Hi, thanks, I pulled the plugs this morning, all 4 are black carbon soot but especially the 2nd plug from the left....a plug website says "Overly rich fuel/air mixture, dirty air filter, too much driving at low speeds, or idling for a long time" .... and recommend "Switch to “hotter” plug. (The higher the plug number, the hotter the plug.)" The plugs are the D8ES, I always thought the lower number like a D7ES would be hotter....anyways what you think about the second plug ? also how do I lean out the mixture ? cheers ...mnot sure if this will foul the plugs but I ride around the 3 to 4 k RPM, maybe I should not be shifting up as I do and keep her in the higher revs ?
heres a cool description from NGK:
Causes of Carbon Fouling:
•Continuous low-speed driving and/or short trips
•Spark plug heat range too cold
•Air-fuel mixture too rich
•Reduced compression and oil usage due to worn piston rings/cylinder walls
•Over-retarded ignition timing
•Ignition system deterioration
Pre-delivery fouling:
Carbon fouling occurs when the spark plug firing end does not reach the self-cleaning temperature of approximately 450°C (842°F). Carbon deposits will begin to burn off from the insulator nose when the self-cleaning temperature is reached. When the heat range is too cold for the engine speed, the firing end temperature will stay below 450°C and carbon deposits will accumulate on the insulator nose. This is called carbon fouling. When enough carbon accumulates, the spark will travel the path of least resistance over the insulator nose to the metal shell instead of jumping across the gap. This usually results in a misfire and further fouling.
If the selected spark plug heat range is too cold, the spark plug may begin to foul when the engine speed is low or when operating in cold conditions with rich air-fuel mixtures. In some cases, the insulator nose can usually be cleaned by operating the engine at higher speeds in order to reach the self-cleaning temperature. If the spark plug has completely fouled, and the engine will not operate correctly, the spark plug may need to be replaced and the fouling cause identified.