new chinese 110 atv with no spark

i´ve just bought a new chinese 110 atv for my son, i dont know which brand it is, all i know is that is called a Falcon 110 ccm.
When i try to start it i can hear the starter engine run but thats all....my neighbor took out the plug and did the `plug to engine test`and said there was no spark at all. He said it could be a broken capacitor.Is he right? could it just be a bad plug? I´ve read some of the earlier posts and can see there are some kill switch problems, could i have one too? There should be a tether kill switch on the rear but there isn´t, the wires are there but no switch connected, is that a problem? Should i bypass the wires or is it okay as it is.
Hope you can help me!
(pardon my english, i am from denmark)  

I need more info on that missing tether kill switch:  When you say it is missing, are you talking about the pull cord and plug that attaches to the tether switch, or are you saying the entire switch is missing including the switch base and pig tail wires which would connect to the wiring harness?

If the entire tether switch is missing that is not a problem.  If just the tether switch plug and pull cord are missing then that is a big problem.  The way this switch works is that the tether plug, when inserted in the switch base, forces the spring loaded tether kill switch open, allowing spark.  When the pull plug is removed the switch snaps closed, killing the spark.  If the entire switch is removed (or simply unplugged from the wiring harness) then the quad is left in the "run" position.

Is this your CDI?



If you unplug your CDI and then measure the resistance of the kill switch pin in the wiring harness to engine ground, it should read open (infinite ohms) when the ignition switch is on and all the kill switches are turned off.  If it reads low ohms to engine ground (i.e. shorted to ground) then you will never get spark.

This is the place to start. Most no spark issues are related to kill switch problems.  If this is not an issue on your quad there are more tests than can be done in the next steps...  

I have a 97 Yamaha big bear and my carb isn't getting gas. What could be the problem? I took it off and exchange the parts. It runs and good when its on choke but when I take it off choke and give it gas it dies out.  

thanks for helping me.
I´ve measured the resistance from the kill switch wire to ground with all the kill switches turned off (that means no tether kill plug connected, and turned off the red button on the left handle) and it reads ca. 1 ohm!!  

stefansolberg:
thanks for helping me.
I´ve measured the resistance from the kill switch wire to ground with all the kill switches turned off (that means no tether kill plug connected, and turned off the red button on the left handle) and it reads ca. 1 ohm!!

Make sure that you had the ignition switch in the "on" position when you did the resistance test.  This switch is a two section switch, and one of the two switch sections is a kill switch.  It is what turns off the quad when you turn the ignition switch to the "off" position.

There are up to 4 kill switches on 110cc machines, any one of which can prevent spark.  They are:

1) One half of the two section ignition switch
2) The left handle bar kill switch
3) The tether pull cord kill switch
4) The remote start/stop radio link module (if installed)

If all the kill switches are off and you still read low ohms then start unplugging the switches one by one until the resistance goes to open (infinite ohms).  If all kill switches are unplugged and you still read low ohms then you have a pinched wire in the harness which is shorted to ground.  

well i dont have the tether installed and there is no remote control, so that leaves only two kill switches the ignition and the red button on the left handle!
maybe i got a little confused by the english language (on/off is the opposite in danish sometimes) so i will try again....
When the red button on the left handle is in RUN position (showing the atv is ready to start) there is infinite ohms and when i press the red button (showing the atv NOT ready to start) i measure ca. 1 ohm!
I am sorry if I misunderstood you  

Infinite ohms on the kill switch when the quad is in the "ready to run" state and shorted to ground when "killed",  means the kill switch circuitry is working.  So we need to look further...

But before we do, how sure are you of your neighbor's diagnosis of "no spark"? If you want to verify this for yourself then here is a very good video link on how to do this:

http://www.reliableatvs.com/movies/sparkplugs-finding-spark.html

Assuming we are still working on a no spark problem, then the next step is to measure the stator ignition related outputs.  The stator provides power and timing info to the CDI.  All of these tests are done with the CDI unplugged:  

1) With the CDI disconnected measure the AC Ignition Power pin voltage to ground on the wiring harness connector.  Set your meter to measure AC volts on the 200 volt scale.  While cranking the starter motor you should read 80 volts AC.  This voltage is what powers the entire ignition system.

2) Now measure the resistance to ground of the same pin in the wiring harness using the ohms scale.  What do you measure?  Do this with the engine stopped.  It doesn't matter whether the ignition is on or off.

3) Measure the AC voltage on the Timing Trigger pin of the wiring harness to ground.  This will be a much smaller voltage so set the meter to a 1 or 2 volt scale.  Your should read 0.3 to 0.5 volts AC while cranking the engine.  This is a signal voltage that tells the CDI when to fire the spark plug.

4) Measure the resistance of the same pin to ground on the ohms scale.  What do you measure?  Do this with the engine stopped.

While you're at it measure the resistance of the Ignition Coil pin in the wiring harness to ground.  It should read less than 2 ohms.  This test measures the connection from the CDI output through the wiring to (and through) the ignition primary winding to ground.  

my neighbor checked the spark the right way.
Here are all my measurements:
wiring harness kill switch to engine ground=infinite
wiring harness AC ignition power pin to wiring harness ground (while cranking)=0 Volts!
wiring harness AC ignition power pin to wiring harness ground=infinite Ohms
wiring harness Timing trigger pin to wiring harness ground (while cranking)=varies a lot but mostly around 0.2-0.5 Volts
wiring harness Timing trigger pin to wiring harness ground=infinite Ohms
wiring harness Ignition Coil Pin to Wiring harness ground=infinite Ohms  

There are some discrepancies in your measurements that need to be resolved.  You report infinite ohms for these three windings:

1) AC Ignition Power (should read about 400 ohms)
2) Timing Trigger (should read around 150 ohms)
3) Ignition Coil Primary (should read about 2 ohms)

It is extremely unlikely for all of these to go bad at once.  Therefor I suspect measurement error, or maybe the ground wire in the wiring harness is not really connected to engine ground.  So first measure the continuity from the ground wire in the wiring harness to engine ground.  It should be zero ohms.  If it reads infinite then check your meter by shorting the two probe leads together.  If that reads infinite your meter is bad.

Make sure you are set to a high enough scale to read the ignition power and timing trigger winding resistances.  400 ohms is the same as 0.4 KOhms.

It is beleivable that the timing trigger voltage measurement is bouncing around a lot.  It depends on the meter design.  The voltage here is actually very narrow +/- 5 volt high pulses with relatively long periods of zero volts in between.  Meters aren't really designed to measure this sort of voltage waveform.

But at the same time it is not likely that you would measure voltage on the timing trigger pin and not be able to measure the resistance of the same winding.  If the winding is open you would not get voltage.  This is whay I suspect some measurement error has occured.  

it reads infinite ohms when i measure wiring ground to engine ground!
I have checked the meter and it is okay!
when i measure timing trigger to engine ground i get 1 ohm!  

Both of those measurements are not right.  The timing trigger measurement that you report sounds more like the ignition coil resistance.  Are you remembering that the pin out on face of the wiring harness connector is mirror imaged from the pin out on the CDI picture I posted.  You have to flip the wiring harness connector over to plug it into the CDI, which reverses the connections left to right.  

You are right I forgot to mirror it! I´m sorry. (maybe I should check the wiring in my brain also!)
Here are all my new measurements:
wiring harness ground to engine ground=0.7 Ohms
wiring harness AC ignition power pin to wiring harness ground (while cranking)=0 Volts!
wiring harness AC ignition power pin to wiring harness ground=infinite Ohms
wiring harness Timing trigger pin to wiring harness ground (while cranking)=varies a lot but mostly around 0.2-0.5 Volts
wiring harness Timing trigger pin to wiring harness ground=120 Ohms
wiring harness Ignition Coil Pin to Wiring harness ground=2 Ohm  

Now everything is making sense.

The AC Ignition Power connection is bad, while everything else looks OK.  Look at the wire color for the AC ignition power pin on the CDI connector.  Find the same color wire coming out of the wiring harness and going into the stator through another connector set.  Usually this is a black wire with a red stripe, though that is not true 100% of the time.  [The stator is inside the engine under the flywheel, so the stator wires will be coming out of the engine cover.]

Disconnect the connector(s) at the stator and remeasure the AC ignition power connection reistance to engine ground (looking into the stator).  Is it still open?  It should be about 400 ohms or so.  If it is still open then the stator is bad and will have to be removed.  If it reads good here then the wire from the stator connector to the CDI is open.

If you do find that the stator AC ignition power winding is open inside the stator then I'd remove it and inspect it for buying a new one.  Sometimes open wire connections are easy to spot and can be fixed without having to buy a new one.  

thanks a lot i will look into it tomorrow.
maybe i have a question or two when opening the engine...  

I have now measured the resistance from the CDI wiring harness AC ignition all the way to the AC ignition in the stator and it measures 1 ohm and i also get 1 ohm when measuring ground from harness to stator. I can´t see anything obviously wrong with the stator, but you know me and mechanics, so i´ll try to get a new stator..