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Coil & plug cap testing


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I'm doing some maintenance on my Banshee, and I'm down to cleaning all electrical connections and grounds. Without the plug caps my coil tests well within spec. With the plug caps on the wires the secondary reads 15.71k. Plug caps read 4.6k and 4.95k. Coil is oem and caps are NGK about 6 months old. Why the high resistance with the caps on?

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You should be fine.  Some aftermarket caps will measure slightly different but where concerns come in is when resistance is WELL out of range.  Slightly out of range is not a concern as temperature can easily alter returned values, as does the meter itself.  

In our electronics work, we typically test a meter against a known high accuracy resistor to ensure meter accuracy.  It is good practice and resistors are VERY cheap!  

 

Also FYI, do NOT use resistor type spark plugs such as BR8ES.  adding additional resistance to the plug will only further reduce spark energy.  

 

 

Brandon

Mull Engineering

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My concern as I am well out of range on the secondary resistance 15000 is more than double the 7100 Max as stated in the manual I've heard that higher resistance like this is bad for CD eyes I don't know being too worried here or not but double the resistance is stated in the manual set me some concerns I

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3 hours ago, IceracerX said:

My concern as I am well out of range on the secondary resistance 15000 is more than double the 7100 Max as stated in the manual I've heard that higher resistance like this is bad for CD eyes I don't know being too worried here or not but double the resistance is stated in the manual set me some concerns I

You are reading that wrong.  The ignition coil by itself (no caps) will read between 4.7-7.1 kohms.  The caps will be around 5kohms each.  Add all that up and you have a circuit test with caps of about 15kohms.  There is nothing wrong with you bike.  Keep in mind, when testing in these ranges a few Kohms is nothing I would get worried about unless the system was not operating correctly.  Typically we will see things swing well into the the mega ohm area when bad.  

 

This is the same as adding 3 resistors in series, NOT to be confused with parallel.  In series, you simply add them.  

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