Hello, I am really at my witts end here, Having followed all previous threads regarding "no spark problems" and working through solutions posted by Lynn and others, I deducted that a new cdi was needed found a good deal on fleabay including coil and plug. Installed new components and yahoo we had spark. Turned it off helped daughter put on helmet and boots and tried to start up and nothing dead as a dodo. wiggled wire coming from starter and away she went good as new ( It even felt as though starter had a bit more go then before) as I pushed the bike out of my shed it dropped down a 2 inch gap in the paving and it stops dead again. So we pushed it back in the shed to have a look and now it turns over however there is no spark. I have a 5 pin cdi with kill switch disconnected at present so it cannot short out have remeasured ac voltage from stator appers to be about 45 volts not getting a confident pulse from trigger though lowest setting on multimeter is 200 volts ac and it is registering about .2 v intermittently. there does not appear to be any voltage coming out of cdi to coil. I think it is possiably the pulse trigger that is at fault but am not sure why it would be an intermittent problem.

I am now very confused and frustrated and will very much appreciate any assistance offered.

 

This comment sticks out. See below...

If the trigger voltage is just barely too low (and falls under a trigger threshold voltage) you get no spark. If it is slightly above the threshold you get spark. But not only that, the first time it fires the engine speed increases a bit which makes even more trigger signal, so you get great spark and the engine fires up. The voltage out of the trigger winding is directly proportional to engine speed. At idle (1500 RPM) the voltage will be 2.5 times the voltage while cranking at 600 RPM.

You said you wiggled the starter wire and it cranked more robustly, and it starterd up. Faster cranking = higher trigger voltage.

Try this experiment:

Jump the quad to you car. Start up the car with a fast idle. This will raise your quad battery voltage to 14 volts or so, so the quad will crank slightly faster. Does the quad start up when you do this?

If so the next step would be to check the gap between the pickup coil outside the stator and the raised bump on the flywheel that does the triggering as it passes under the pickup coil. Decreasing this gap *greatly* raises the trigger output voltage. I don't know what the proper gap should be on your quad, but as a benchmark eton quads specify this gap at 0.025".

 

Thanks for your assistance Lynn, I was unable to start the bike using jumper leads, It does not appear that the pulse trigger gap is adjustable on my quad so perhaps I should just replace the entire stator/magneto unit with a new one.

 

Since everything has been changed except the wiring and the stator the possiblities are getting less. Before buying the stator disconnect the CDi and measure the resistance of the trigger wire to the ground wire on the CDI connector. It should be 150 ohms or so, and it should be constant. While measuring this resistance wiggle the wires around at the CDI and stator to see if you can make it change. Also inspect the connections at the CDI connector to see if the slide on pins are looking loose or opened up.

You get nothing at the CDI output (to the coil). You get intermittent voltage at the trigger input, and good AC power voltage to the CDI. From the data given everything is pointing to the trigger coil in the stator.