![]() Reduced compression and oil usage due to worn piston rings/cylinder wallsĬarbon fouling occurs when the spark plug firing end does not reach the self-cleaning temperature of approximately 450☌ (842☏).Continuous low-speed driving and/or short trips.The heat range must be carefully selected for proper spark plug thermal performance. If the heat range is not optimal, then serious trouble can be the result. The optimal firing end temperature is approximately 500☌ (932☏) to 800☌ (1472☏). The two most common causes of spark plug problems are carbon fouling ( 800☌). A colder spark plug functions in an opposite manner. The insulator nose of a hotter spark plug also has a greater surface area that is exposed to more of the ignited gases and is easily heated to higher temperatures. Therefore, the path for the dissipation of heat from the insulator nose to the cylinder head is longer and the firing end stays hotter. The insulator nose of a hotter spark plug has a longer distance between the firing tip of the insulator and the point where insulator meets the metal shell. A hot-type spark plug has a longer insulator nose. The major structural difference affecting the heat rating is the length of the insulator nose. Relative position of the insulator tip to the end of the shell (projection).Structure of the center electrode such as a copper core, etc.Thermal conductivity of the insulator, center electrode, etc.Surface area and/or length of the insulator nose.Some basic structural factors affecting the heat range of a spark plug are: Heat rating and heat flow path of NGK Spark Plugs The heat rating of each NGK spark plug is indicated by a number lower numbers indicate a hotter type, higher numbers indicate a colder type. The heat range of a spark plug is the range in which the plug works well thermally. The spark plug heat range has no relationship to the electrical energy transferred through the spark plug. This is called “thermal performance,” and is determined by the heat range selected. The spark plug firing end temperature must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. A sufficient amount of voltage must be supplied by the ignition system to spark across the spark plug gap. Spark plugs must provide a path and a location for electrical energy from the ignition coil to create a spark used to ignite the air-fuel mixture. The primary function of the spark plug is to ignite the air-fuel mixture within the combustion chamber under any operating condition. The experienced tuner can use spark plugs to find the root cause of problems, determine air-fuel ratios and increase vehicle performance. The spark plug displays the condition inside the combustion chambers of the engine. Spark plugs are a “window” into the engine and can be a valuable diagnostic tool. This basic guide is designed to assist the technician, hobbyist or race technician in understanding, using and troubleshooting spark plugs. I don't need it for show off, it simply sometimes helps to smothen some flat spots and prevent stalling.Spark plugs have been around as long as internal combustion engines have and are often a misunderstood component. Hell, i was riding my bikes with it completely turned off. Pump is not too much- it should give brisk response on minimum out, without black smoke from the pipes. You're sure they didn't turn the adjustment screw out more?Īlso, you might wanna check the operation of your enricher circuit[ might not sitting down /close completely- thus sucking in the extra gas.Īnd see if you acc. On my 96 s&s i use 29.5 intermediate and on 113- i use i think 31.īut it doesn't explain why you started to foul the plugs now. I was under impression tha the correctly intermediate jetted g carb should have the mixture screw somewhere within 1-1.5 turn out range running smoothly at idle and up to 3k rpm[ having it at 3/4 out indicates that the used jet might be a bit big. Put in a new set yesterday, fired right up. The last set of plugs i put in were a set that had approx 2500 miles on them, pale white in color, gap at 40, went approx 30 miles & pulled them out.black as hell. Could i have another problem other than the settings that is causing the fouling plugs. The carb is an s&s g.the accelerator pump is approx 4 turns out & the air mixture screw is approx 3/4 turn out. The bike runs great with no hesitation when she the motor is running. Now the bike has been in the shop for some other issues, & i don not know if anyone has messed with the carb while is the shop. I normally change out plugs around every 2500 hours & they were a pale white. I pull the plugs & they are black as brick of coal. ![]() In the past several months my 07 iron horse has been very hard to start.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |