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Wow shure is informitive reading this :) i love to learn,,,,, wish i had this drive back in highschool.......
 
Hoople said:
Very True Glider. But I won't rest until we all truly understand how it works.
At this moment all we really know is that it works and it needs to be left alone. But hopefully with the info we gather and Delphi's reply to my questions we may have the insight as to what is really going on. I am sure you will agree.

This much I can tell you.
1) The Ion Sensor electronics are built into the encapsulated coil. Use a different coil and you have no Ion detection Sensor.
2) The Ion sensor determines combustion PRESSURES by sensing back EMF from the secondary spark gap.
3) The Trigger information from the coil is sent to the ECM and the ECM compares it to a software value. The software value is FIXED and can not be changed using a SEST. Therefore my belief is that if you do anything to change the "normal combustion pressure", the EMF will change and the Ion sensor will not trigger at the correct threshold point.
Click to expand...

I think we pretty much said the same thing :D

ION Sensing Explained - Harley Davidson Community
 
I just ran out to the shop and quickly tested about 16 plugs I have, used and new, I am getting no consistency at all with either the HD or the champion plugs. Some HD plugs are reading <10 and others are over 30. The champions are worse, some read infinite and one is >50....

The good news is my main bike is old... as long as they fire, they will work. I still am very unimpressed with the consistency...

What next, are we all going to bring our meters into the store and test each plug until we get the proper resistance range?

I heard a rumor once about plugs sold at both Canadian Tire and Walmart. I was told that they buy the lots from the manufacturer that didnt pass the QC. Something like that when the manufacturer tests 1 plug in a batch of 100 and it fails, they toss the whole batch and move on, and these are the ones the large discount stores pick up for cents on the dollar. If this is true, could that be why my Champions are so unconsistent? I did buy them @ Canadian Tire.
 
As with most things that are mass produced, they will vary greatly from one to the next.

You can use whatever you wish but I have had the least of any problems with the recommended plug for the application sold by the manufacturer.
 
What year models are effected by ion sensing, is this a twin cam thing, all years of the tc, or does this go back to evo also?
 
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