I had the engine out of my quad to paint the frame and when I refitted it my quad will not start because there is no spark. It seems to crank ok. I have checked the cdi and i think it is a DC one. I followed the troubleshooting procedure for it and found the following...

1) Unplug the CDI. Turn the ignition switch on. Set all kill switches the the "run" position. In the wiring harness, look to see if you have a wire on the kill switch pin. If you do, measure the resistance of the kill switch pin to the ground pin on the 20K ohm scale. It should read infinite ohms (same as when the meter leads are hanging free and not touching anything). It should not read zero ohms (shorted). OK

2) Leave the CDI unplugged. Turn off the ignition switch. Set your meter to the lowest resistance scale you have (like 2 ohms or 20 ohms full scale). Measure the resistance of the "Ignition Coil" pin in the wiring harness to the ground pin. You should read something around 0.7 ohms (but not zero ohms). What do your measure? 0.8ohms

3) Leave the CDI unplugged and the ignition switch off. Set your meter to the lowest resistance scale you have (like 2 ohms or 20 ohms full scale). Measure the resistance of the "Ground" pin in the wiring harness to the the negative battery terminal. You should read zero ohms. What do your measure? 0ohms

4) Leave the CDI unplugged, and turn the ignition switch into the "on" position. Use a meter to measure the DC voltage on the pin labeled "AC ignition power" in the wiring harness to the ground wire on the 20 volt DC scale. You should read battery voltage (12 volts). What do you measure? No Voltage at AC Ignition power

5) Leave the CDI unplugged. Use a meter to measure the resistance of the "Ignition Trigger Pulse" pin in the wiring harness to the ground wire on the 2K ohm scale. You should read approximately 150 ohms. What do you measure? About 108ohms

6) Set your meter down to the lowest scale you have for measuring AC volts. 2 volts would be ideal, but some meters don't go that low. In that case use the lowest scale you have. While cranking the engine, measure the voltage on the Ignition Trigger Pulse pin in the wiring harness to the ground pin. You should measure 0.2 to 0.5 volts AC. What do you measure? 0.15 Volts

7) Now plug the CDI back in. Measure the AC voltage on the Ignition Coil pin to the ground pin using the 200 volt scale. If you have to, use a sewing pin to poke through the wire insulation and then put the meter probe on the sewing pin. But don't hold your fingers on the connection during the next test - there may be high voltage here when the engine is turning. With the ignition on and all kill switches set to the "run" position, crank the starter motor. You should see voltages bouncing around at random values and the meter captures all or part of a spark event. What do you see? Nothing

I have also had a look at all the connections and cannot see any breakages.

 

I have to ask the question: How do you know that this is a DC powered CDI? There are two avenues here:

1) You really do have a DC powered CDI, and you don't get 12 volts to what I call erroneously call in my picture "AC ignition power" [see Note 1 below]. That would be a problem, and we need to go down that path - if you have a DC powered CDI.

2) If you have an AC powered CDI, then you *will* have "no voltage" in your test step (4) response above.

We need to unambiguously determine if you have a DC powered CDI or an AC powered CDI to continue...

So here is the procedure for determining which you have:


[Note 1]: Six pin DC powered CDIs and six pin AC powered CDIs look the same, and cannot be distinguished by appearance alone. In my photobucket picture links I took a big shortcut and used the same picture for AC and/or DC powered CDIs. But the "power pin" is labeled "AC Ignition Power" when, in fact, it is "DC Ignition power" on a DC powered CDI. Don't let my laziness confuse you. I will fix this someday when I have some extra time...

 

Thanks for the quick reply. My mistake about the cdi, after testing again I saw ac voltage when cranking with the ignition on between the ac ignition pin and ground pins on the cdi. I will search for the ac cdi testing procedure now and then I will post my results here...

 

So I have followed the testing procedure below and this is what I have found....

To troubleshoot no spark problems on a 6 pin AC powered CDI it makes sense to start in the middle (the CDI), measure as much as we can and branch out from there. For the CDI to do its thing it needs power, a trigger pulse, and it must must be inhibited via the kill switch input pin.

1) Unplug the CDI. Turn the ignition switch on. Set all kill switches the the "run" position. In the wiring harness, measure the resistance of the kill switch pin to the ground pin on the 20K ohm scale. It should read infinite ohms (same as when the meter leads are hanging free and not touching anything). It should not read zero ohms (shorted). Infinite

2) Leave the CDI unplugged. Use a meter to measure the resistance of the AC ignition power pin in the wiring harness to the ground wire on the 2K ohm scale. You should read approximately 400 ohms. What do you measure? 258 Ohms

3) In a similar fashion measure the resistance of the Ignition Trigger Pulse pin to the ground pin. You should see 150 ohms or so. What do you measure? 108 Ohms

4) Switch your meter over to measure AC volts on the 200 volt scale. Leave the CDI unplugged. While cranking the engine, measure the voltage on the AC Ignition Power pin in the wiring harness to the ground pin. You should measure 40 to 80 volts AC. What do you measure? 45-65 Volts

5) Set your meter down to the lowest scale you have for measuring AC volts. 2 volts would be ideal, but some meters don't go that low. In that case use the lowest scale you have. While cranking the engine, measure the voltage on the Ignition Trigger Pulse pin in the wiring harness to the ground pin. You should measure 0.2 to 0.5 volts AC. What do you measure? 0.150 Volts

6) Now plug the CDI back in. Measure the AC voltage on the Ignition Coil pin to the ground pin using the 200 volt scale. If you have to, use a sewing pin to poke through the wire insulation and then put the meter probe on the sewing pin. But don't hold your fingers on the connection during the next test - there may be high voltage here when the engine is turning. With the ignition on and all kill switches set to the "run" position, crank the starter motor. You should see voltages bouncing around at random values and the meter captures all or part of a spark event. What do you see? Nothing

 

Sounds like a bad CDI. You've got all the proper inputs to the CDI: A trigger signal, adequate AC power, and a good ground.

You've got no voltage to the ignition coil on the output side of the CDI. You've got the proper resistance looking into the ignition coil.

And no spark.... It points to the CDI...

It is possible that there is a shorted turn in the ignition coil that could bring the output voltage to the coil to zero because it's input inductance goes to zero, but this is very unlikely.

It is also posssible that you've made some measurement errors, and based on this we are going down a dead end street. Even if I was there and made the measurements myself, I would still put this possibility near the top of the list. I always measure again and again, just to make sure. It is so easy to make a mistake, and then you're off down the proverbial garden path...

So please redo you test measurments just to make sure, then look at the CDI. But it seems unlikely that your CDI would fail just because you painted the frame. This is another reason to recheck your measurements...

 

Ok so eventually got some time to get back to this. I rechecked the measurements twice and have got the following:
1. Infinite
2. 281 Ohms
3.105 Ohms
4. 52-53 Volts
5. 0.170 Volts
6. Nothing

I have tried a new CDI and I am getting the same values. I have also fitted a new coil and still no spark.

 

Any luck mate im having the same issues, randomly started firing ran good then i turned off n wont spark again.