spark – Airheads Beemer Club

Numerous problems can occur if your engine’s spark plugs are not correct or not working properly; or, there are problems such as tight valve clearances, improper carburetor mixture adjustments or jetting, needle settings, worn engine items creating excessive oil burning, ETC. Spark plugs are ‘read’ by looking at the combustion chamber end of the plug. You can look at the color and deposits from combustion and determine a fair amount…with some practice. It is not just the condition of the normally near white or light tan or orange color of the central electrode insulator, but the condition of the outer and central electrode and the color and look to the metal on the flat end portion of the spark plug, which is about 1/8th inch wide. Once you gain experience [it doesn’t hurt to ask SEVERAL supposedly experienced mechanics to confirm your analysis], you will find that much can be learned from a look-see. Spark plugs are looked at to determine if they are worn to needing replacement; to see if the engine seems to be operating correctly; and to get some idea of specific problems. Reading spark plugs is somewhat of an art, requiring experience. Experience is especially needed with modern unleaded fuels, most of which contains alcohol and other ingredients that makes reading spark plugs even more difficult, as the ‘old colors’ do not always apply. SOME things never change, however, so, read on. You should have a working knowledge of spark plug heat ranges, proper torque setttings, whether or not to use an antiseize compound on the spark plug threads; and what the proper spark plug caps are for YOUR motorcycle.

An in-depth article on spark plugs, problems with newer Bosch Spark Plugs; and chart of all three Bosch spark plug numbering systems; chart of Bosch versus NGK; and a listing of NGK spark plug caps, and much more, such as use of antiseize compound, etc., is here:

http://bmwmotorcycletech.info/sparkplugs.htm

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The following article is a SIMPLIFIED explanation of ignition systems, although lengthy. There is CONSIDERABLY MORE technical information, including repairs, etc., in the author’s website, particularly here:
http://bmwmotorcycletech.info/ignition.htm

A common type of ignition in very early cars consisted, typically, of wooden boxes, with a vibrating electrical contact which sent battery energy into a coil of a modest number of turns of wire wound on an iron core located inside the box. There was another coil of wire wound on that iron core, with thousands of turns, and these turns ‘transformed’ the lower voltage of the ‘primary winding’, fed by the battery, to a few thousand volts, and this was applied to the spark plugs. In most early engines the spark was applied continuously. Somewhat later a rotating switch was used. It had a contact or close by contact, one for each cylinder, and this was called a ‘distributor’. The only problem with the vibrating contact system is that the spark output can not be set to ‘fire’ the spark plug at a very specific piston position, although the distributor method helped SLIGHTLY. With the very low compression ratio and very low power output of these engines, together with the very long stroke and large diameter pistons, these ignition methods worked OK. As engines improved in various areas, the need for better and more precise ignition came about.

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Tag: spark

Spark Plugs – Reading Them

Ignition Systems; historical & modern