Hi I've been reading this thread and have some questions. I just got a 2006 tank quad I think it is a 90 cc. I have a no start problem, thought it was the CID and took it to a shop to get a new one. They plugged it into another quad and it fired, said it was good. So I have a 5 pin CID,i saw where you said take the safety out of it so I did. Still no spark. I check and see power coming from the CID wire to the coil when cranking as long as I didn't connect it to the coil. Once connected I am not seeing power and get no spark. So I thought it was a bad coil,replaced to coil and still don't seem together spark. What steps should I take from here? Thanks

 

Does your CDI look exactly like the five pin CDI earlier in this thread? Is your quad a four stroke? I tried to search on google for Tank ATVs, but got zillions of links for ATV gas tanks .

You're confusing me when you say you took the "safety out of it". Are you talking about the kill switch wire on the CDI? Or are you talking about the starter motor safety interlock?

The kill switch pin on the CDI is not a safety device. It is just a method to kill spark so you can shut off the engine. It is no different than having a switch to turn off a bedroom light. One wouldn't normally call a bedroom light switch a safety device - hence my confusion.

The starter motor interlock circuit *is* a safety circuit that won't allow the starter motor to turn when you push the start button unless the brakes are applied. This is sort of like the safety interlock that won't let your start up a car in "drive". The idea is that you dont want a quad to start up in gear, and take off unexpectedly. This *is* safety circuit, but it has absolutely nothing to do with spark.

Do you see why I'm confused? So please explain exactly what you mean, and what you actually did to take the "safety out of it" so I can follow along .

How are you measuring this "power"? I hope you're using a meter. If so, then what scale is the meter set to, and what values did you read? The devil is in the details. There is much information there in the meter results to help solve this problem.

I hope you're not using a test light. Those are totally worthless, and a total waste of time for these types of problems. Ideally what you need is an oscilloscope, but that is out of reach for most people. So a meter is the second best thing. They're cheaper than test lights (isn't that ironic...) and so much more powerful. A fairly good one is about $20.

First step is to get a meter and learn how to use it (with guidance of course). Assuming you have a four stroke quad with the the 5 pin CDI posted earlier, then go through the tests one at a time and report all the results. If you get stuck on a step post back on how/where you're getting stuck and I can provide more detail.

There is a lot of stuff going on in an ignition system. It is all AC (not DC - there is no 12 volt anything on a five pin CDI ignition system). A lot of it is high voltage, some very narrow pulsed high voltages, and some low voltage narrow pulses as well. You need a meter.

BTW, measuring voltage at the output of a CDI to the ignition coil with the ignition coil disconnected is a totally meaningless measurement. The CDI must have the ignition coil hooked up to function at all, and different CDI designs will give different results for this totally off the wall and meaningless "test".

 

Just registered to say a hearty thankyou to LynnEdwards for the advice here and on China Riders.

I bought a nondescript 50cc ATV for my Godson with no clue as to whether it would ever run as the previous owner had butchered the wiring loom to take out all the safety switches. In the process he'd messed a few other things up. With help from this thread and others, I worked my way around the loom, re connecting and repairing until I got down to the last problem. This really stumped me as I was sure that I had every wire in place and all the meter readings within tollerence. After a couple of hours of head scratching I realised that there was one thing I hadn't checked; the CDI ground ("earth" in the UK) was broken at the connection in the plug. A quick 10 min repair and the little beauty was sparking like a good un. Without doubt, the most valuable advice was to look at the loom as two systems, 12v and AC. It helped a lot.

On firing up there was an obvious feuling problem caused by a dodgy in-line filter. With that sorted, the quad pulls like a train.
Now to build a little trailer.

Again, thanks Lynn, for the time and effort you've put into this excellent resource.

 

New to ATVs. Bought a 2005 Moontrax 90 that did not start.

1) Cleaned the carb like 7 times (gas turned to gunk) and was able to get atv running/ but with erratic idle... like it would rev really high. The electric start didn't work so I just start it by kick start. That worked for like 1 week.

Now it just won't start at all. It sounds like it wants to turn over but I think its not getting spark at all.

Started looking into the electric system... why does my atv look like it has 2 CDIs connected together. Please look at picture and help with identifying my wires..?

Thanks in advance from a complete newbie.

http://i938.photobucket.com/albums/a...psc3bbca78.jpg

 

I just want to say a big thanks to all the people that help on here!
I was given 2 chinese quads that wouldn't work and the owners gave up.
both had electrical problems that both turned out to be kill switches. also as they had been sitting around for ages, they both needed the carbs cleaned out. I have one running perfectly and the other still needs a little more work.
it will idle but won't rev, I am guessing I need to clean the carb out again, there must have been a little bit of crap still there.

Just a side note, when I did get the second one running, it revved veeerrry slow and that was all it would do, It ended up being a blocked fuel tap, of all things.

anyway, thanks again.

 

Hello i have a 2006 chines 250 atv, i havd the carb cleaned out last winter after they got that done it ran fine. Tgey had it running tgen it just shut off and i havent been able to get uy started since. I get no spark i change the cdi coil and spark plug still no spark. When i measure voltage from coil to ground while trying to start it i get readings but wont start. Please help

 

Hi everyone been reading the threads and seems this is a common problem. Pretty mech. incline and this issue has me pre-plex. I disconnected the the kill switch wire at the cdi and started up, adjusted the new carb and was running better than it ever had. Pulled the spark plug cap to shut off. waited a few min. connected the spark plug cap and it started back up. Came back in to read some more on this issue. Went back out after 10 min and will not start same issue no spark kill switch wire is still disconnected. Any direction??
Thanks

 

Lynn Edwards is smart and knowledgeable on things that spark. I can never say enough good things about the information he offers.

 

I have the same problem have chack all of the kill swithes ever thing is right. on cdi exserp there are no ac voitage on the iginition coil pin to ground

 

I read one of the previous forums and ran through their diagnosis. Same problem, plug is good but no spark. After dropping the CDI unit from under the seat I removed the center wire(kill switch) and I got it fired again no problem, but I couldn't shut it down except to choke it out. Now I just don't know if there's a way to bypass that wire or do I have to pick up a new CDI unit?
Separate problem,
Wouldn't run properly unless choke was on near full. Found the air filter neck was almost completely severed and found a replacement but still can't get it to run well. Does anyone understand the manual directions on carb adjustment?