"People say" spark plug polarity is important. But:
1) Why? If the spark is at say 10,000 volts, why should adding or subtracting 12 volts matter?
2) How are magnetos arranged? Does the spark polarity depend which way the magneto turns? If so, which ones give a better spark? Nortons or lesser machines where they might turn the other way? (Obviously they are independent of any battery that might be fitted.)
3) Can spark polarity be checked? (I'm thinking about magnetos)
4) Last week I bought a new strobe light. It has a clip (inductor?) to put on a plug lead. (Incidentally these are far more convenient than the ancient ones I have which interupt the igntion lead...) But it seems to be sensitive to which way round it goes. How can that be? And is that the way to work out polarity of my spark? (I could try and calibrate the best way round by fitting to a plug lead on my car - assuming VW arrange the correct polarity).
1. If you look in Roadholder…
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Further...
Further, adding 12V to 10Kv is of course nonsense. But spark polarity is also dependant on a phenominum known as Thermionic Emission. Too long to explain here so you have to do your own research.
As for the magnetos questions-ask your magneto repair man-if he doesn't know then find another magneto repairer.
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The twin cylinder magneto's…
Simple as this: spark plugs work better (or at least spark at lower voltage) one way than the other.
The twin cylinder magneto's two sparks are of opposite polarities.
A dual output ignition coil, which is common on electronic conversions and old Jap bikes, causes two coincident sparks of opposite polarities.
As we've all experienced, bikes (and cars) can run perfectly well with some plugs sparking the "wrong way."
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The electrodes of spark…
The electrodes of spark plugs are made of diferent materials . Ignition coils were marked with polarity for a reason. No one is saying that the plugs wont work with incorrect polarity . But will they work well for long?.
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"No one is saying that the…
"No one is saying that the plugs wont work with incorrect polarity . But will they work well for long?"
Are people actually still asking if 1960s-onward Japanese twins and fours, with wasted spark ignition "worked well for long?"
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1. If you look in Roadholder 324 November 2014 you will see why spark polarity matters.
https://www.nortonownersclub.org/html/archive/rh/324/14/index.html
2. No idea on this one, but see 4 below.
3. Again, see below.
4. The clip clip that goes over the HT lead is looking for a positive going pulse to fire the strobe, if the clip is the wrong way round then it sees a negative going pules and it does not fire. So this is a good way to check for 2 and 3 above.