(I posted this in the kids quads also)
oops, just read rule number 3 about double posting, sorry

Hello everyone.

I am fixing a 2002, Western Auto quad, model ATV90X10, (Chinese ATV). It has a 90cc, 2 stroke engine. I was told that "Squirrels" ate the wiring harness, but I think the "squirrel" walks on 2 legs and weights about 180lbs or so. Anyway, the owner bought a used wiring harness to replace the old one but it is not even close to fitting. (I was handed the old wiring harness, in pieces, wadded up in a Zip-lock bag.) I have been able to reassemble the old harness back together, but now I have no spark. I do not have the voltage regulator (it is fried) hooked up, but the battery is hooked up and everything else works. I need someone to check my hook up of the CDI. My CDI has 5 wires: black/red, blue/white, green, (these three wires are loose with their own plug connections), then black, and black/white wire which are in a 2 pin plug.

Currently I have them hooked up as follows:
black/red - black/red of stator
blue/white - blue/white of stator (pulse generator)
black - ground
black/white - kill switch (ground in "Run")
green - coil
These all follow the wire color codes of the rest of the bike.

I have checked the coil, plug wire, and the plug. The stator metered OK. I get 4 - 6 volts on the 2 AC charge wires. 50 -70 volts on the ignition (black/red). The pulse signal (blue/white) is about .6 volts. These are with me turning it over using my hand with the kick starter.

Any suggestions?

Is there a way to check a CDI?

Bruce

 

I don't know anything about this quad. So I'm just making some educated guesses...

The green wire for the output of the CDI to the coil I've never seen before. Green is usually ground. Is the coil primary input wire really green? If you disconnect the CDI and measure the reistance of the green wire to engine ground, what resistance do you get? Other than the green wire the rest of your connections seem pretty standard.

Also, be sure to measure the harness blue/white wire resistance to ground at the CDI connector (CDI unplugged). Measureing the AC voltage is not a good enough test by itself. Often an open trigger coil will allow a small AC voltage to appear on the trigger wire due to stray capacitance to adjacent wires in the harness. You're looking for something like 150 ohms.

Measure the resistance of the black wire at the cdi connector to engine ground. It should be zero ohms.

Are you sure about the kill switch connection being grounded in the "run" state? Some quads are like this, while others have the spark killed when this wire is grounded. I would try kicking over the engine both with the kill wire grounded and open.

 

The green wire for the output of the CDI to the coil I've never seen before. Green is usually ground. Is the coil primary input wire really green? I agree, it usually is, but the only green wire on the quad is the one on the coil.If you disconnect the CDI and measure the reistance of the green wire to engine ground, what resistance do you get? Other than the green wire the rest of your connections seem pretty standard.I can see both ends of the green wire that hooks to the CDI. The coil even has a green terminal on it. The green wire from the CDI connection to ground has about 4 or less ohms to ground. This is what I read when I check through only the coil.

Also, be sure to measure the harness blue/white wire resistance to ground at the CDI connector (CDI unplugged). Measureing the AC voltage is not a good enough test by itself. Often an open trigger coil will allow a small AC voltage to appear on the trigger wire due to stray capacitance to adjacent wires in the harness. You're looking for something like 150 ohms. This maybe the problem I got infinite ohms when I just checked it. (It was OK before.) And it is still putting out .4-.6 volts

Measure the resistance of the black wire at the cdi connector to engine ground. It should be zero ohms.The black wire that hooks to the CDI connector is zero ohms to the engine and frame. I checked.

Are you sure about the kill switch connection being grounded in the "run" state? I am sure, I checked it several times. I expected it to be open in "run" and grounded in "off".Some quads are like this, while others have the spark killed when this wire is grounded. I would try kicking over the engine both with the kill wire grounded and open.I already tried that too.

If the green wire is ground then which one goes to the coil?

 

My responses in red:

 

Lynn
Just to let you know a little of my back ground, I am an retired Air Force aircraft avionics technician, with my Airframe and Powerplant license. I have experience dealing in all sorts of mechanical and electrical systems on heavy equipment, aircraft, automobiles, boats, motorcycles, appliances and many others. (reading this sound like I am bragging )

I thought the 4 ohms was a little high also, so I did some checking and found the four ohms through the coil is because the batteries in my meter were low. I just replaced them and now it is about .4 ohm. The pulse generator is still infinite ohms.

I agree the pulse generator is a good place to start now that I caught it screwing up and will see about getting a replacement.


PS: I too like high voltage though I prefer it in a shower. LOL


Bruce

 

Im kinda wondering why you cant fix it yourself.. just kidding...

Welcome to the forum KB2!

 

mywifesquad

I thought I could, but this has been kicking my butt. I usually have some kind of reference to work from, (wiring diagrams, schematics, technical manuals, etc) to guide me. Even when I deal with something strange I usually find something that I can use. This quad does not seem to conform to anything I have been able to find. I had to basically build a wiring harness for this thing. I used about five different diagrams to piece it together. Not to difficult, but I can not get the CDI to work. So now I have resorted to my last reference "the guy down the street" or in this case the internet.

I have learned 2 very important things over the years: first, to work smart, not hard, second, to learn from other people's experiences. It is usually lot less painful and always cheaper.

Bruce

 

Welcome to the forums.

Heck, with that type of background, scrap the motor that's in there and replace it with a F119-PW-100.

Might want to keep the kids off it, and watch out for that first corner.

 

I would except you suck up everything around you and when you go to full power all the kids in the neighborhood line the street holding long sticks with marshmallows and hot dogs on them for when you go by. Then there is the problem of the way the rider is positioned on the engine (which gets very warm). I kind of like that area of my anatomy un-roasted.

Bruce

 

Well finally got the right magneto coil assembly. I had to change a couple of wires on my CDI. but I finally got it started and it runs great. Thanks for the help. I would post a diagram of how I wired this if I knew how.