fpd4308

I was wondering which side of the stock harley coil is positive as neither post is marked. I have heard that as long as you put all the positive wires on one post and the grounds on the other it doesnt matter but wanted to check with the experts.

Thanks

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BUBBIE

If post are color like gold copper brass = positive... While silver is usually negative..

Signed....BUBBIE

Hoople

It does make a difference. Reversing the polarity on the primary side changes whether the spark will jump from the shell electrode to the center post tip or from the center post tip to the shell electrode. It is always preferred to have the spark jump from the hotter electrode to the colder hence center to shell.

Reversing the polarity will not prevent the bike from running. It will just require more ionization voltage to jump the gap.

glider

You can check the polarization of the spark by using a lead pencil point inserted between the plug wire brass and the spark plug tip. See which way the spark arks. If it arks to the plug you are wired correctly.

Safehaven

Hoople already gave the answer that the polarity of the coil will direct which direction the plasma arc will be initiated from (cathode or anode). Since the center pin will generally run a bit hotter, it will be a bit easier to initiate the spark, but your bike will run either way. The difference is marginal..

ultrat

I must be dense,, i read Gliders post several times,, then i got it...

fpd4308

Awesome..thank you all for the help.