Definitive answer to Tec KP03

J

jimbo

New member
Location
Wallington, Surrey
Do the dual coloured wires go to black terminal on coil and solid colours to green terminal. I've searched through this forum and so far I have found a post that say this and another that says the opposite. Answers please from those that have fitted PK03's.
Cheers
 
Your question can't accurately be answered without knowing what bike you have, or what ignition. But as far as TEK coil polarity is concerned Green is -ve and Black + ve
 
Tactfully answered Rob :D 

I sometimes find it a little amusing (and confusing) when questions come up about wire colours. So after years of exhaustive study and experimentation, I've come up with a new electrical law. I think it's just as profound as Ohm's law.

My new law (let's call it Cam's Law) states that "The electrical properties of a cable are unaffected by the colour of its insulation".
 
jimbo said:
Fair points, should have said it was RGS Corsa, so where should the positive lead run from so that I can trace it back.
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In that case, the orange/white is the live +12v supply. If you have still them, that colour changes at the resistors above the HT coils. They can/should be removed
 
Piranha Brother 2 said:
Thanks Cam - about to run wires to my Dynas!  :-*
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Check whether the coils have any markings to identify positive and negative. The coil will work either way, but there is a preference for which way the spark jumps across the plug gap (centre spark plug electrode should be negative). The difference is only marginal though. You get about a 15% stronger spark with the correct polarity. It's something to do with the relative temperatures of the spark plug's electrodes making it easier for the current to flow one way than the other.

On parallel twins (or a 180? triple) with a wasted spark, it's normal to use a twin outlet coil so the current flows in one plug and out the other. Therefore one plug will always be "wrong" regardless of which way you connect the coil primary. In that case it's not worth the hassle of thinking about it.  But I believe you're creating a twisted twin that must have a separate coil for each plug, so you'll be able to get both plugs firing the right way.

If there are no polarity markings on the coils, you can still get it right by testing the spark plug polarity. Connect a digital voltmeter with the negative lead to the plug terminal and the positive lead to the engine. Set the meter on the highest DC volt range and briefly crank the engine. The meter will flash up a momentary or fluctuating voltage reading. Don't worry about the actual number, just look for a "-" sign. If it reads a negative voltage, the plug polarity is arse about. In that case, swap the primary leads on the coil.


PS: If you have a cheap crappy multimeter, the high secondary voltage could damage it. But any half decent meter will have over-voltage protection and it's only a very brief transient voltage peak, so it should be OK. If you're worried, put a resistor in the coil primary circuit to reduce the primary (and therefore the secondary) voltage. Something like 20 Ohms should suffice.
 
Piranha Brother 2 said:
thanks Electroprofessor Cam!
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Nah. I'm an oily-fingered mechanical engineer. I learned everything I know about automotive electrickery from the internet and clever people like John Wilson.
Haven't heard from John for ages. I wonder how he is.
Just checked his profile. He hasn't logged in since April 2019.
 
Well, you investigate a lot deeper than I do! I'm pretty good at the basic + - stuff, volts and amps. Starting to get more into ohms but generally if something doesn't work, my brain just looks for a test part from another vehicle to ascertain a fault.
 
Piranha Brother 2 said:
I'm pretty good at the basic + - stuff, volts and amps. Starting to get more into ohms ...
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They're all related. Vehicle electrics are just an array of pretty simple DC circuits that obey a couple of basic principles.

Ohm's Law (V=IR) is the most fundamental electrical principle and is relevant to 90% of bike electrics. (V=Volts, I=Amps, R=Ohms)
The next most useful thing is the power equation, P=IV=I2R (P=power in Watts).

Voltage is a constant (nominally 12V) so the only variables are current, resistance and Power. If you know any one of those variables then you can work out the other two from the equations above.

Use adequate cable sizes for the current they're carrying and that's pretty much it. What could possibly go wrong?

A couple of footnotes:

You rarely need to consider parallel circuits in automotive electrics, but if you do, then Kirchoff's current and voltage laws come into play. Look 'em up on the web if you need them.

Ohm's Law is inadequate when you get into AC circuits, but you don't need to worry about AC as long as there's output from your alternator. If the alternator fails, then it's usually a replacement job unless you can find a wiring fault.

Some people find it useful to consider the flow of water in pipes as an analogy to the flow of electricity in electrical circuits.
Voltage is equivalent to pressure
Current is equivalent to flow rate
Resistance is the resistance to the flow in both cases
 
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