I bought a couple of chineses quads this weekend (labeled 125cc, but actually 107cc). One ran great, but all of a sudden quit last night. I pulled the plug, and there is no spark. It is still the factory plug until I can get another, but the plug is good. Swapped it with the running quad, and get good spark with both on that one.

It turns over, but just won't fire. Is the CDI the box under the seat? Where is the fuse? I'm not great with electical diagnoses, so don't know where to start. I've read a few post about disconnecting the black/white wire to see if it is the kill switch, but just wanted to make sure I knew where to look. I don't have a voltmeter, but may pick one up when I get some NGK sparkplugs on Saturday. Thanks for anything you can give me to point me in the right direction.

 

Three common CDI's in no particular order:







Can you find any of these on you quad?

The main fuse is *always* real close to the battery plus terminal, or off the big fat red wire at the starter solenoid (follow the fat red wire from the battery plus terminal). But if your starter turns with the start button then your fuse is fine.

 

Thanks for the fuse info. I was just going to check that first, because I know they sent two fuses with the quads, so I was hoping for an easy fix. Seeing the rubber sleeve around the CDIs you attached, I'm sure it is right under the seat on mine. I'll check it out tonight. Based on what I described, does that sound like the likely culprit?

 

Disconnected the kill switch wire from the CDI, and it fired up. Do I assume the kill switch is bad, or could it be somewhere in between? Runs fine w/o kill switch enabled, but cannot shut it down without disconnecting CDI again.

 

Now your problem is much easier. There can be up to four kill switches on your quad. All the kill switches are wired in parallel, so that when any one of them is shorted to ground the spark is killed. By disconnecting the wire at the CDI you guaranteed that the kill switch connection can't be shorted to ground.

Take a meter and set it to measure ohms. Measure the resistance of the dangling kill switch wire in the wiring harness to ground. It will read zero ohms. Disconnect all the kill switches (by unplugging them) at the wiring harness connector one at a time until the resistance goes to infinity (open). Then you've found the bad switch.

The possible kill switches are (you may not have all them on your quad):

1) Handlebar kill switch
2) On half of the two pole igntion switch (this section of the switch is what turns your quad off when you turn off the igntition).
3) Tether pull cord switch (safety device that kills the quad when a cable is pulled off).
4) Remote Control module (this module has the ability to shut down the engine remotely using the kill switch wiring)

 

LynnEdwards, thanks for your help. Turned out to be something easy. I borrowed a meter thinking I had three switches to test. Decided to start with the remote, and follow up with the ignition and thumb switch. Started following wires trying to find where the remote went, and saw a cap not quite on. Realized I had four kill switches with the new-found tether kill. I put the cap on tight, plugged the wire back in, and everything was fine. Felt like a fool, but at least I learned a few things. A couple of days ago, I didn't know what a CDI was, how to get a wire free from the wiring harness, or that I had four kill switches on the atvs. Information that I am sure I will use at some point in the future. Never too old to learn a few things, I guess.

 

Your welcome for the help. I'm glad you got it running again...

 

Lynn, your threads still live on! Just found my problem, my kill switch on my handlebar was grounding out! I wasn't going to give up until I got it fixed, been fooling around with it for several ours and finally decided to get professional help. As Gomer Pyle would say, "Thank you, thank you, thank you."

 

Your welcome .

 

Hi I'm having the same problem. I have the second CDI, I pulled the kill switch and still nothing, does that mean its the CDI? Thanks for any input, its driving me nuts. I had spark and then had a short, I changed the fuse and still nothing. I think having a negative get hit with a positive which popped my fuse might of fried the CDI.