Spark Plug Boots

My dealer couldn't (or wouldn't) get them, Freddie had them to me the next day. Try the sorce!!!
 
My coils were wearing the threaded area on top of plugs and building up a lot of dust/dirt. I was told this build up was caused by arcing from the coil to the plug and was caused by excessive wear of the coils. Yamaha is aware this is a problem and replaced all four of my coil/plugboots under warranty.
 
Re: Spark Plugs

bigtimesledder1 said:
I can't believe a colder plug ( 2 Electrodes or not) makes more horse power nor can any local techs at the YAMI DEALERS

Bearing in mind that the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water journals. This means the plug has a higher internal temperature, and is said to be a hot plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.

Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range is necessary when the engine is modified for performance, subjected to heavy loads, or is run at high rpms for a significant period of time. The colder type removes heat more quickly, and will reduce the chance of pre-ignition/detonation and melting or damage to the firing end. (Engine temperature can affect the spark plug's operating temperature, but not the spark plugs heat range).
 


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