Hello,
I just purchased this quad and washed it. After washing it ran terrible for about 15 mins then would not start. I found the CDI box had come loose from the frame and water was sitting in the connected and one of the ground pins looked like it had gotten hot and shorted. I replaced the CDI box and the quad was running good for about 2 hours then it died and now it will not start again. I have already ordered two more CDI boxes as I think that is the problem but I was hoping someone here could confirm what I think. Readings were done with a fluke meter. 6 pin AC CDI box

Ignition trigger pulse pin 125 ohms to ground, .9 volts when trying to start
AC ignition power pin 129 ohms to ground, 60 VAC when trying to start
Ignition coil pin .7 ohms to ground, cannot remember for sure when starting but think it was 1.2 volts, I will recheck this.
Kill switch to ground OPEN with key on, closed with key off.
Ground pins .4 to ground

All tests were done with the CDI unplugged.

Thanks in advance for any input!!!

 

This is a twin (two cylinder) quad? I've never seen one like that.

All the readings sound OK. The AC ignition power resistance is usually about 450 ohms, but you have 60 volts AC cranking which is good (and more important than the resistance). But I'm also assuming a single cylinder generic chinese CDI.

If the new CDI doesn't do it then there is the spark plug (or plugs) and the coil.

 

Thanks for the reply Lynn! Yes its a twin, two spark plugs! So you think its safe to change the coil/plugs if the CDI does not do it?

 

That's what I would do. CDI first, then coil/plugs.

 

Hey Lynn,

I figured it would be better to post here rather than private so others may learn something that are having the same problem. I found out that I should have spark to both plugs at the same time on this twin quad even if the ignition coil on one side is bad the other should have spark but I do not. Do you have any other ideas on what could be the problem? Another thing I did not tell you before that might be a clue is after washing this quad and replacing the burned up CDI box when the quad was running the kill switch would not work so I had to kill the motor but choking the carb. Could this have fouled the plugs? I only did it about maybe 5 times. Also the new spark plug i'm using to check for spark by grounding to the engine is not the correct spark plug for this, its a auto spark plug, could that not spark even if everything is correct? Also at one point when messing with it I could wiggle the gear shift foot peg and could kill all power to the quad when doing this but now when I wiggle the shifter it does not kill power. Does any of this info help you in where I should go next? The spark plug cap on one side was bad and I"m waiting for a replacement but I have a very strong suspicion that it is still not going to fire as I do not have spark to the other cylinder. Thanks in advance,

Ryan

 

Ryan,

Since I''ve never seen a twin cylinder chines ATV, everything I say about this problem is somewhere between an educated guess and pure conjecture.

Check out this diagram:



The diagram has a dual coil ignition system which appears to use two separate outputs on the CDI to drive the two coils, and it appear to use the 2 and 4 pin connectors which may be the same as your quad. Does yours do this? It is not the same as a generic 2 and 4 pin CDI. If you look at the wire harness wire colors does each coil primary have separate colors, and do both these colors appear on separate pins at the CDI? Or do both coil primaries have the same color wire driving them in the wiring harness, and this color appears on only one pin at the CDI?

If there is really only one output driving the coils, and both coils are wired in parallel to each other, then one bad coil could conceiveably consume all the CDI output and prevent the other from generating spark. Hooking up only one coil at a time would let the good coil spark when it was connected all by itself.

Where did you buy the CDI's? Do you have a link?

 

Thanks so much again Lynn!!! I would be screwed without your help!!! So it turns out that each ignition coil has its own wire going to the CDI!!! I must have the wrong CDI then. What I dont get is one of the CDI's i bought was from a local shop and it was $49.99. The quad ran for about 2 hours with this CDI before it quit. If it was firing on only one cylinder would you think I would have noticed? So i'm not sure if this was the correct CDI or not. When I bought it the dude seemed to know about it being a twin atv but said "oh yea thats the standard CNI". Keep in mind this is my 1st quad. The other two were purchased here:
Chinese ATV Parts - Go Kart Parts - Scooter Parts - CDI Boxes - CDI #19 for Chinese ATVs Scooters Dirt Bikes Go Karts

This is the actual one I purchased which I know is wrong. So I'm not sure if I should buy another one from the same place or if I should try to find one elsewhere? I have sent an email to the place online above to see what they say. Do you know anything about this type of CDI that has two ignition coils going to it?

Thanks again for all your help!

 

Sounds like the wrong CDI.

So know we know about *three* versions of CDIs that look identical. AC powered, DC powered, and now *2 coil* AC powered .

To review:

You had a burnt CDI. You replaced it and it worked for 2 hours, then died. The new CDI(s) didn't work, but we now know they were definately wrong, and couldn't have worked.

So it seems the next step is to get another CDI from the local shop since it did work for a while. Chinese CDIs aren't thoroughly tested, and infant mortality in new electronics is common. Is there any way your local shop can test the CDI out before leaving the store?

I don't think an engine would run on just one of two cylinders at all.