I have two magnet marelli coils I want to check that I am wiring them up correctly. They have two terminals a single spade connection with an R next to it. I take it this is the terminal for the green and red connections
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Re: Coils on a Le Mans 3
One on each coil. The other a dual spade connection which should join together the two coils and the live terminal coming through from the ignition module. Is this correct. I have a broken screw cap for the HT lead on one that needs replacing I'll try to source one if not does anyone one have a spare lying about.Cheers Guys,I am trying to get the beast firing again, having problems, I am using a Newtronic system.,Knock the centre out of an old plug so that you can slide a scewdriver or similar through it.
Put a timing disc on the front of the engine (alternator)
Rock the engine back and too past tdc noting position, say 2.00mm either side of tdc (with a dial gauge on top of the screwdriver).
Centre, then touch the flywheel here with a drill point.
Turn engine back required amount (34 degree?) and touch flywheel with drill point again.
I do different colours left and right than I know which cylinder Im looking at.
Ignore every other mark on the flywheel.
Set to these marks at 5000 rpm with strobe
Can't set Newtronics static ,,,
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the blank one and you can check this out after the bike is running or at least when you get the coil to fire by placing the lead part of a pencil in the gap between the spark plug or a good ground and the gap between the pencil and the spark plug wire so you can see the spark jump to the plug or ground from the plug wire and if the spark flash is on the wire side of the pencil the coil the coil is wired with wrong polarity if the system is a positive ground system. The coil will work no matter what the polarity ie no matter which of the terminals you connect to power and which you connect to ground, the only difference will be a somewhat weaker spark if electron flow is reversed from what it should be i.e. if it is from negative or ground to positive on a negative ground system or as on some older British ignition systems from positive to negative on a positive ground system. The flash will appear on the side of the pencil lead away from the current flow i.e. the flash will occur as the current leaves the pencil lead. Hope this helps.
All relays are coils that turn into electro-magnets when energized by power to both ends of the wire that forms the coil. A break anywhere in the wire (open)causes the relay to fail. The relay can also fail from a short (usually the varnish insulation on the wire sometimes break down from heat or physical damage, and then one part of the exposed wire contacts another part of exposed wire and the power takes a short cut instead of traveling the designed route). Relays can be tested by using an ohmmeter(with power isolated) to check the continuity across the coil. With the power off, measure the ohms from one side of the terminal that that the coil is attached to the other. An "OL" or infinite reading is a open coil. The coil should show a moderate reading. To check the relay with power on, do the following. Attach a voltmeter to the terminal on the relay that receives the power to operate the coil (same terminal as mentioned in first example) and make sure power is available there. All the normally open terminals or connections should have power, the normally closed should not be energized. Measure all terminal with one lead to ground and the other to the terminal when checking for power (this can be done while the relay is still attached to the equipment.A relay can also fail because of defective contacts.
If you have 3 wires it's most likely a single fire coil. Meaning one spark per cylinder. A dual fire will typically have two wires and fire both cylinders at the same time, but only one will produce power since it's on the compression stroke and the other cylinder isn't.
Basic coil tests are for Primary and Secondary ohms (resistance) values and I.B. or an Insulation Break meaning you have a short.
Refer to your owners manual for what type of coil you have. Different models have different ohms ranges. This test would be for a typical 3-5 ohms single lead externally grounded coil. You can usually identify an Externally grounded coil as they are grounded by the mounting fixture itself. TOOL REQUIRED - VOLTMETER that will read ohm values 1. DISCONNECT THE BATTERY NEGATIVE CABLE 2. If the coil is in the bike disconnect wires from the two terminals to isolate it. 3. Once you set your Voltmeter scale to ohms connect the red and black leads to each terminal. You should read between 3 and 5 ohms if that is the spec for your bike. You have now tested the primary circuit of your coil. If you read Infinity ohms replace the coil, you have an open circuit or break in your coil winding. 4.Now take your black lead off one terminal and connect it to good ground, battery negative cable or non-painted frame bolt. Your meter should now read 0 or OFL (off line). If you do get a reading here your coil has a break in the insulation and is shorting out. Your only option here is to replace the coil. 5. Repeat step 4. for the other secondary terminal. Red on terminal, black to ground. It should also read OFL.
Another quick test option regardless of type of coil is to check Volts going to the coil with battery connected. If you have a 12vdc system and you are getting close to 12vdc at the coil terminal and nothing is coming out of the coil you either have a bad coil or connection.
The coils primary circuit terms. should be labeled "+" and "-". With key on check for 12v @ wire to "coil +" and "coil -" grounds through points. When ground's removed (points open) magnetic field collapses inducing high voltage (spark) in "secondary" circuit.
This is strange. I've been working on Harley's for almost 40 years and I've only run into two bad coils on the later model bikes. Are you using original equipment coils? If so, are you using the correct ones?
Coils come in different varieties for different uses. There are coils made for racing, road use, electronic ignitions, and points type ignitions. The coil you want is for road use with electronic ignition. If you use a digital volt ohm meter and test the resistance of the primary winding of the coil, it should check out at between 3 and 4 ohms. The "primary" winding is the coil of wire inside the coil that goes from one small terminal to the next. Put your DVOM leads on the small terminals, one lead on each terminal, with the meter in "R x 1" position. It should read between 3 and 4 ohms.
If your bike has points in it, your are correct. There is usually a black wire that goes from the points directly to the coil. When the points open, this breaks the circuit and the current through the coil stops. This, in conjunction with the action of the condensor, collapses the magnetic field in the coil's primary circuit wiring. The collapsing magnetic causes and induced high voltage low amperage current in the coils secondary circuit. This the high voltage that produces the spark at the spark plug.