hi i have no spark on my sons atv i'm lost now i changed the cdi box the coil and the stator and still nothing i read what lynnedwards wrote and tested like he said my meter setting on ac volts the lowest is 200 and when i test the ac igntion i get 50 volts when i test timming trigger i get zero so then where do i go from here reading on ohms is 130 please help my son really wants to ride this thing he is 5 now my other 2 sons gave this thing a good ride and now it's the little ones turn.

 

But did you check the kill switches? That is the most common cause of no spark?

200 volts AC as a lowest scale for measuring trigger voltages can be a problem. If you are able to measure trigger voltages of 0.2 volts AC, and also measure 0.0 volts AC when the engine is stopped, then this is good evidence that you have adequate trigger voltage.

On the other hand, if you measure 0.0 volts (200 volts AC scale) when cranking, and 0.0 when stopped, then this could be that you have no trigger voltage, or your meter is off by just 2 least significant digits (a very REAL possibility - especially on cheap meters). This is a dilemma...

Can you find a better meter? You can buy one for about $20 USD. It's a lot cheaper than the dollars you already thrown at replacement parts . Borrowing one is OK too, but if you got a better meter and learned how to use it your experience with chinese quads will be a lot better .

But do check the kill switch circuitry first...

 

Hi yes i checked the kill switches i removed the grey wire from the cdi box and cranked still no fire i took my meter from that grey wire to ground meter goes to zero any other test i can do to check the kill switch? and ok i'll go buy another meterto better read the trigger voltage.

 

hi lynn ok got a new meter and read the voltage on the timming trigger my reading is 0.010 volts ac and 133ohms what next ?

 

These two tests are a little contradictory:

1) If you disconnect the kill switch wire that should enable spark (gray is a very non-standard color for the kill switch BTW - most kill switch wires are black with a white stripe). Please double check and make sure you are actually disconnecting the kill switch wire at the CDI.

2) But here's the contradictory part: You say you measure the wire resistance to ground and get zero ohms. That is the condition that will kill spark if that wire was hooked up to the CDI. You should be reading an open circuit. Did you do this test with the ignition switch on, and all other kill switches in the "run" position?

 

0.010 volts will not trigger the CDI. Let's make sure you are using the meter correctly. What brand meter? What scale are you on? Double check the values you gave. Make sure the decimal place is in the right position...

If you consistently measure 10 millivolts AC (0.01 volts AC) then this is a definate problem to dig into deeper. But let's get the possibility of measurement error out of the way first...

 

Hi lynn ok lets start over the reading for the kill switch is not zero to ground i misread it o.l open line when i turn off switch then zero to ground the meter i bought can read as low as 5 ac volts. the cdi box has five wireslooking at your pic trigger on top left blue/white top right ignition coil blue/yellow bottom right ac power black /red bottom left ground green bottom center kill switch grey.but if disconnect the wire (kill switch) should i not get spark?so then problem is not the kill switches bad stator? the voltage on the timming trigger is 0.010volts.

 

Yep, your wires look right. All the colors are standard except the kill switch. So Gray wire to the kill switch connection it is .

10 millivolts AC (0.01 volts AC) on the trigger wire is wrong. It is almost like it is shorted to ground, but you measured 130 ohms, so it is not shorted. It is possible for a stator to have shorted turns in the trigger coil which would measure close enough on the ohms test, yet generate zero volts (10 millivolts is really close to zero), when cranking. And you've also changed the stator. Maybe your original problem was something else and you've installed a bad stator. This is why I really don't think throwing parts at the problem is a good strategy. Often you end up with two problems to fix instead of just solving the original problem.

Please don't discount measurement error. Even the most seasoned technicians make measurement mistakes. It is important to remeasure your previous findings, and make sure they are *always* 100% the same each time. Today, tomorrow, last week, the measurements should always be the same... I can't be there to watch so make sure you're 100% convinced you're measuring thing right .

Do you still have your old stator? What does it's trigger winding measure for ohms? Is it the same 130 ohms? You can measure ohms without mounting it back in the quad.

As far as kill switches go, if you disconnect the kill switch wire (or it measures open to ground [o.l.]) then that enables spark. If the kill switch pin on the CDI is shorted to ground (zero ohms, or 0.00 ohms) then there will be no spark.

Remember that you've changed stuff from the original configuration where you first ran into trouble. If you've bought and installed a bad part then now you have more than one problem which more like 10 times harder to fix than just the original problem.

 

Ok old stator yellow 1.7 blue/ white 133.3 white 1.9 black/red open green 0.0 new yellow 1.2 blue/white 133.3 white 1.4 black/red 0.51 green 0.7 I checked 3 times and yes I have all the old parts when I get back home gonna put the old stator on and check the ac voltage and the trigger voltage that I get

 

If the black/red wire to ground is open on your old stator, then that is definitely a problem on your old stator. That's the power winding for the CDI.

So it could be that you've changed out a bad stator (with a CDI AC Power winding problem) to a stator that has a trigger winding problem.

Since your old stator has an open power winding it might be worth poking around in there before reinstalling it. You may just have a broken wire at the connection to the high AC Ignition power winding (or a bad ground at the other end). You might be able to just fix the old one. Just keep in mind that any fix you do must be able to survive in a high temperature, high vibration environment. Everything must be fastened down so it can't wiggle, and it must be able to withstand 100 degrees C [in other words, a wire nut and electrical tape repair won't cut it...]. Solder is OK. Shrink tubing is OK. Non corrosive curing silicone rubber is OK (like Dow 3145).