well i got it for $50 and it ran. it had idle issues so we took care of that, did some riding for a day or 2 then decided to weld up a extended trailing arm, turned out great. then we decided to revise the shock placement and add heavy duty foot pegs. well my brother forgot to remove all the electronics before welding this time. the coil wires started smoking as he was welding, so they were removed and replaced. then its wouldnt do anything run/start.

so i started to inspect the rest of the harness, come to find out someone had previously removed the voltage regulator and done some "crack head" wiring job on this atv. handle bar start/killswitch didnt work, only started with remote. headlights didnt work, pull cord killswitch didnt work.

so i removed all the wiring/electrical accesories to make the elec system as simple as possible to make it easier to find the problem. i hooked up the starter relay with a on/off toggle switch, now it cranks but doesnt have spark. i hooked up the cdi to the stator matching the 3 wires (triggr/triggr,grnd/grnd,ac-pwr/ac-pwr)with the 4th cdi wire for the coil(coil/coil pos.,) ive tried having the 5th wire for the killswitch unhooked,grounded,and to power with none showing spark while cranking. also as i do not have the volt regulator im not quite sure what to do with the 2 yellow wires that went to the regulator coming out of the stator harness.

i think it could be a bad coil, but with not knowing the original factory wiring im running into problems.

the wire coming out of the top of the coil is what i believe to be the pos and the lower wire on the heat sink as the neg for the coil. correct me if im wrong, ive had the wire i believe to be the ground grounded.

all i want is to get spark for the plug, i dont need lights/alarm/remote/killswitches. i have the starter taken care of it works correctly. do we need the cdi to get spark or can i bypass it and directly wire the trigger signal wire to the coil. i want the wiring as simple as possible like my kawasaki kdx50(one wire from the stator to the coil, and 2 wires from the coil to the kill switch.) this atv needs to be as light as possible, no extras and the electronics simple/reliable just whats need to provide spark for the motor, i have the starter taken care of already.

any help would be great, i can provide pics if needed. i just want this running again, please some one help me out....its amazing, i can build a drag car but this atvs messed up wiring is stumping me.

 

When wires smoke that means lots of current went through them. That also means the current went through the coil primary winding also. I'm thinking that your coil is now melted inside.

I'm assuming that this is the CDI you have, correct?:




If so then don't worry yet about the voltage regulator. It is there to keep the battery charged and run the lights without draining your battery while the engine is running. They have nothing to do with ignition. Get your ignition working first, then tackle this later. Leave the two yellow wires dangling (but tape them up so they don't short together or to ground).

Could you post a picture of your coil? I'm not understanding the top and/or heat sink description. BTW, if your CDI is the one pictured above then ignition coils for all quads that use this CDI will work. No need to be brand specific when shopping for another. If you can get it fit mechanically it will work.

No, the CDI is very necessary. To fire the spark plug you need a lot of power dissipated over a very small fraction of a second. To do this a special high voltage winding on the stator (AC ignition power) provides a power source that over one entire revolution of the engine charges up a storage capacitor (stores energy). At the proper time a signal from the trigger wire tells the capacitor to dump all its energy onto the ignition coil (in a fraction of a second) which produces a spark.

You know, the CDI works very much like a standard flush toilet. After a flush, the city water pressure (think AC ignition power) comes in through a small pipe that over time and fills up a storage tank (think CDI storage capacitor). At the proper time someone wiggles a little lever (think ignition trigger signal) which causes the entire contents of the storage tank (i.e. capacitor) to get dumped into the bowl (ignition coil primary).

On your toilet if you hook the small water line directly to the bowl it won't get the job done at all. And no matter what kind of contrivance you try to attach to that little flush handle - it won't get the job done either without a full storage tank to back it up.

I tried, but I couldn't come up with a better analogy. Sorry.

 

no that explains alot accually, i just wasnt sure weather or not the cdi was just a relay for the spark signal to be circuted&amplified through. that is the cdi it has. thanks for your help ill get pics of the coil up tomorrow. what happens with the wire thats not connected to the cdi coming from the coil? also what needs to be done with the kill switch wire coming from the coil? i have a feeling
if i switch out the coil and finish up my wiring q's the little beast will run again.

thanks again for your help, if u ever need anything along the line of forced induction/tig welding/custom fab/projector-LED retrofits let me know.

 

The kill switch wiring goes all over the place, but not to the coil. At the CDI, the kill switch connection should be open (no connection to ground, or infinite resistance to ground) to get spark. It is grounded to kill spark and stop the engine. Be aware that when the engine is cranking over, or running, and the kill switches are all off (run position), there is high voltage on this line (several hundred volts at high engine speeds) so be careful.

The kill switch wiring goes to the handlebar kill switch, one half of the two section ignition switch, lanyard tether kill switch (if equipped), and the remote start/stop module (if equipped). All those switches are wired in parallel so that any one of them can short the kill switch line to ground and kill the engine. For example, the ignition switch shorts the kill switch line to ground when you turn the switch to the off position.

I'm not understanding this. The ignition coil pin on the CDI should should be wired up to the ignition coil primary connection on the coil. The other side of the ignition coil primary is grounded (the ignition coil secondary shares this same ground connection). And of course the output side of the coil secondary winding goes to the spark plug.

 

sry i meant kill switch wire coming from cdi, thats what i needed to know along with how the coil was wired(im used to working with groups of 4 or 8 coil packs). one last question and i should have it running, what are the specs of the coil output/duration. what other coils can be used?

 

i have everything hooked up correctly, but still have no spark. i tried using the coil off my kdx 50 and that didnt seem to provide visual spark either. so i think the coil and cdi both need replaced. arg

 

Not sure what you mean by "coil output/duration". Maybe a picture of what the voltage on the CDI ignition coil pin would help:



There are two voltage waveforms shown because I've two different brand CDI's that are are compatible and make these drastically different coil output waveforms. By far, the most comon CDI design out there is the waveform for CDI #2. Just as there are many ways to flush a toilet, I guess there are many ways to fire a spark plug too.

The waveforms were measured with an oscilloscope, which is just a fancy volt meter that measures fast moving voltages and plots out a graph showing how the voltage varies with time. Voltage is on the vertical axis, and time is on the horizontal axis. Note the huge voltages, and the fact that they are moving back and forth at 30,000 times per second (CDI #2). The ignition coil secondary voltage is higher still by a factor of 100 or so.

As far as what other coils can be used:

The ignition coil and CDI are a matched pair. They are tuned to each other for maximum energy transfer from the storage capacitor in the CDI to the spark plug.

If you look at the spare parts vendors for various chinese quads you'll see that many of them use exactly the same CDI. If they are using the same CDI then all the ignition coils must be electrically the same too. It does not follow, however, that you can use (say for example) an arctic cat coil with a chinese quad CDI. They are not a matched pair.

The two examples of CDI waveforms above are completely different yet they are designed to work with the same coil, so they are a matched pair -even though it isn't obvious by looking at the waveforms.

 

Maybe, but before shotgunning by buying a lot of parts measure the stator outputs, and make sure your wiring at the CDI is correct:

1) Unplug the CDI and measure the stator AC ignition power voltage pin in the harness to ground while cranking the engine. It should be 80 volts AC. Be sure you are measuring AC voltage, and not DC.

2) Measure the Ignition Trigger pin voltage to ground while cranking. You should have 0.3 volts AC while cranking. Make sure you have the meter on the lowest AC scale (like 20 volts AC full scale).

3) Make sure your CDI ground pin in the wiring harness measures zero ohms to ground.

4) Make sure the ignition coil pin in the wiring harness measures 1 ohm or so to ground. It should not read zero ohms.

5) Make sure you still have the kill switch wire disconnected at the CDI. This insures that the kill switch wiring is completely out of the picture when troubleshooting "no spark" problems.

 

in the cdi plug
ac power showed 63-69V/ac while cranking at the harness,with neg probe grnded.
trigger showed .320-.680V/ac while cranking at the harness,with neg probe grnded.
ground showed zero ohms.
ign coil showed zero ohms.

now on to the coil its self?

 

My responses are embedded in your text using the color red:

Lynn Edwards