I have a mojo-pro 80 ATV,, suddenly spark stopped.
No spark, but if i take off battery, let sit for an hour, then re-connect battery used for elec. start i will get spark for a short while,, like 20 seconds.. So somthing is heating up when battery gets attached then no spark.

I say spark w/ my volt meter in the wires to coil,, 45 volts.

So the question i am wondering,,, i know it's not the coil,, cause when i get the 45 volts coil kicks a spark to the plug...

Stator?
trigger? Doubt it
CDI ?


Any thoughts ????

 

Do you feel anything warming up?

Can you heat up individual parts with a hair dryer first and cause failures right off the bat after sitting awhile without the battery hooked up? BTW, removing the main fuse is a lot easier than unbolting the battery cable and does the same thing.

Else you will need to start measuring voltages with a meter while you are getting spark and comparing that to the same voltages when you aren't getting spark.

 

No i don't feel anything getting hot. I do have flywheel on so can't touch stator.
CDI, Stator, trigger,,,,, all being the main components....

What see's current when the battery is hooked up and key switch is in off position ? CDI ?

I know the CDI has a pin for everything on it...?

Can the stator even feel current from battery when ignition key is off ?


I did check ohms on stator before and after,, .383ohms on all the pins when set to 2k....... and when i say before,, thats prior to hooking battery up...


I do not see a "main fuse" on this machine... there is ONE fuse on one of the wires going to battery,,, now and in the past i learned this wire goes to starter....

 

Get a can of "freeze spray" at Radio Shack. It is used to find thermally intermittent components. The cans of dust remover for use on keyboards, camera lens', etc. might work too, but the freeze spray will really cool the component way down.

 

The only thing that possibly sees current with the battery hooked up with the ignition off is the regulator output and any remote control module that you may have hooked up. And only some quads have the regulator wired up before the ignition switch. If the regulator is working the internal diodes block any current from flowing backwards when the engine isn't turning. The remote draws a little (10 milliamps (0.01 amps)) so it isn't much unless you let the quad sit for weeks on end. If the regulator internal diodes are shorted then the current can flow backwards to ground through the stator, but this doesn't sound like your problem. You're having "no spark" issues, not "my battery goes dead in ten minutes" problems.

0.383K ohms (383 ohms) sounds right for one of the stator windings. But you have three - two of which are spark related. They don't all read 383 ohms - at least they better not.

Does your CDI look like this:



Once we nail down which CDI you have, then let's determine if it is AC powered or DC powered (I'm suspeting AC powered at this point). Then once we know that we can start measuring voltages to isolate the problem.

Yes, I shouldn't have used the term main fuse. That implies more than one. My quad only has one, as do most chinese quads. Some do have more than one, and the "main" fuse disconnects the battery from everything but the starter motor path. But note that this fuse does *not* lie in the starter path. The starter motor path is never fused - starters draw gobs of current through big heavy wires- it is everything else that need to be protected because they use those small gauge wires that can't take the full current capability of the battery without catching fire.

 

Lynn, i seen your posts before....

My CDI is AC powered.. No voltage from pin till i crank motor.

All pins from my stator pigtail are 383, ohms, yes all three.


Yesterday i almost got it started w/ starting fluid for that first 20 seconds of spark.

I did the pulling of the safety switches on the pigtail of cdi pins to eliminate that mess,,, still no spark,,, so i put that pin back in pigtail.

 

Oh, and yes,, that is my exact CDI visually.

 

The stator must have at least five wires coming out if your CDI is AC powered:

1) Ground
2) AC battery charge winding side 1 (isolated from ground) (nothing to do with spark)
3) AC Battery charge winding side 2 (isolated from ground) (nothing to do with spark)
4) Timing trigger signal
5) Moderately high voltage AC to power the CDI.

So when you say you measured *all* three I'm confused. There must be more wires coming out of the stator. Look at the colors of the wires in the wiring harness that connect to the stator (not the pigtails colors going into the stator). What are they? What are the wire colors at the CDI connector. What are the colors at the voltage regulator connector (if you have pigtails on the regulator ignore those - report the colors in the wiring harness).

Something is not making sende here. I'm fishing for more clues...

 

Sorry for Late reply...

Wires coming from stator it's self,,, flywheel removal:Yellow, Green, White, Black/Red. Total of 4 wires.
Trigger: Blue/Yellow Total of 1 wire.

Now up the wire harness if i follow the wire bundle from the stator, it goes to one pig tail connection, and two seperate wire pug ins.
That pig tail: Yellow, Green, White.
Seperate: Blue/Yellow
Seperate: Black/Red

Lynn, this is the pig tail i checked for ohms: i put one lead from the meter on the Black/Red as a ground,,, then red meter wire on Yellow, then on Green, then on White.... 383 ohms on all three !!! SAME.



CDI: i will write color to your diagram text w/ location.
Ignition trigger pulse: Blue/White
Ground: Green
Ground: Blank, no pin or wire
To Ignition coil: Black/Yellow

Kill Switch: Black/White
AC Ignition: Power: Black/Red


Ok, now Voltage regulator: On the pigtail that plugs into it, White, Red, Green, Yellow.


Two wires go to coil: Black/Yellow, Green. I have eliminated the coil, cause i check for voltage from the two wires w/ my volt meter... I get 45 volts when she wants to spark...



Ok, I hope that was decriptive, and may help someone else who is reading.

 

You're using the black/red wire as a ground reference. This is not correct. The black/red is the moderately high AC voltage output that powers the CDI. Use ground as the ground reference. You can use frame gournd, or the green wire - either one will work. Now measure the resistance of all *four* other wires:

1) Black/red: around 400 ohms (383 ohms is close enough)
2) Blu/Yel: Aroun 150 ohms
3) White: low ohms (less than 2 ohms)
4) Yellow: low ohms (less than 2 ohms)

All this sounds correct.

But remember that we don't want to diagnose the system when it is working (i.e. "when she wants to spark"). All this does is prove that the system is working. More important is what the coil measures when she *doesn't* want to spark. It is perfectly legitimate to measure the system while it is working, but only to use this info to see what changed or is missing when is isn't working.

If you aren't getting the 45 volt spikes at the coil when it stops working (and you really were getting them before when it was wanting to spark), then the problem isn't the coil or spark plug - it must be earlier. On the other hand if you are getting the 45 volts spikes at the coil primary and you still don't have spark then the coil or spark plug must be at fault.

Things to measure:

1) AC ignition power pin: Measure at the CDI while cranking the engine while the CDI is disconnected, all kill switch in the "run" position. Of course to determine if you have spark you will have to have the CDI in see, then take it out quickly and do the test. You should see 45-80 volts AC at cranking speeds.

2) Timing Trigger at the CDI: Meaasure while cranking the engine. CDI can be plugged in or not. It doesn't matter.

3) Ignition coil output: CDI must be pluggged in. Does this voltage (or the two above voltages) change between spark and no-spark conditions?