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Ignition coils

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oldtuggie:
1976 550 four f1 supersport
Hi can anyone advise me how to use a multimeter  to test a suspected  faulty ignition coils

Bryanj:
Disconnect the coils then do a resistance(ohms) test between the two small leads and again between the two ht leads with plug caps off, also test the plug caps seperately.
Coils rarely fail but plugcaps do

deltarider:
Like Bryan said, all suspect the coils, but usually they are OK. Let's take the stock configuration, meaning OEM coils and resistor plugcaps. The coil has two circuits: the primary and the secundary. The primary should read between 4 and 5Ω, so you select the 200Ω range for this. The secundary circuit of the coil itself, with plugcaps removed, should be between 14 and 15kΩ. To measure an individual, disconnected plugcap, select the 20kΩ scale. Each plugcap should read 5-8kΩ. If you read zero, that cap is not the resistor type and then it makes sense to have resistor plugs because you need some resistance in the secundary circuit. It should be resistor plugs or resistor caps, not both. So in total the secundary circuit will be between 24 and 31kΩ. BTW, for that you need the 200kΩ scale. You could start to measure the secundary circuit in total by just pulling the caps from the plugs and then have one probe in cap #2 and the other in cap #3 and for the other in cap#1 and cap#4. As said the secundary resistance inside the coil itself usually is 14 - 15 kΩ. An individual cap's resistance should not be over 8 kΩ. So with the plugcaps connected to their wires, total resistance should not be over (15 + 8 + 8  = 31 kΩ. If it is, plugcaps should be unscrewed from their wires for individual measuring. I'm not fond of R type plugs. Their resistance tend to increase faster than the resistor caps in my experience. You can measure the R plugs resistance by putting one probe to where normally the cap sits and the other probe to the center electrode (a bit difficult but it can be done). When over 8 kΩ, replace.

JezzaPeach:
Nice one Deltarider, just what I needed too.

AshimotoK0:
HONDA IGNITION COIL REPAIRING WITH NEW HT LEADS

https://www.dropbox.com/s/x0a4fcpmrwm3l19/Ignition%20coil%20fix.doc?dl=0

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