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I have a Jetmoto 125cc ATV. I just cleaned the carb, put new fuel lines on and a new fuel filter on 2 days ago. I was riding it today and it ran perfect. I shut it off to go eat lunch and when I went to start it up it wouldn't fire up. It doesn't look like its getting spark but it was a few minutes before so I don't know what could of changed since then I was running without an airfilter so could the jets be clogged?. I really need help and it would be greatly appreciated.
Did you actually check for spark by removing the plug and holding it up to the engine block while cranking?
How did you shut the quad off? With the ignition switch, or the kill switch on the handlebar? Do you have one of those handlebar kill switches that kills the engine when you move it sideways left or right? Many of those use a spring to center the kill switch and then you must *push* it in till it goes *click* to re-enable spark. I think this is a hand-me-down designed switch where it's original function was as a turn light indicator switch on a motorcycle. There was the left and right positions to start the blinking turn signal lights, then to turn the lights off you pushed the switch button in.
I have one of those dang switches and it fools me often.
Clogged jets have nothing to do with getting spark...
I'm making an assumption that you have a five pin CDI. Below is a generic procedure for troubleshooting "no spark" problems on a 5 pin CDI. If your CDI is four pin then we will need to back up and use a different procedure.
There is no harm in checking / replugging connectors. Often bad connections are the issue. But besides the spark plug, ignition coil, and CDI connections be sure to check the stator connections coming out of the engine, as well as all the kill switches (part of the ignition switch, the handlebar switch, the rear tether kill switch [if equipped], and the remote start/stop module [if equipped]).
Is this a picture of your CDI?
Assuming the answer is yes, the first thing to do is eliminate all kill switches and kill switch wiring:
Method 1) Unplug the CDI and remove the kill switch pin in the CDI connector on the wiring harness. The pin is held in with a spring tab on the pin itself. You'll have to probe into the connector and push this tab in order to extract the pin. Plug the CDI back in (kill switch wire dangling) and see if you have spark.
Method 2) Unplug the CDI. Turn on the ignition switch and set all kill switches to the run position. Use a meter to measure resistance in of the kill switch pin in the wiring harness connector to engine/frame ground. If the reistance is infinite on the 100K ohm scale then your kill switches/kill switch wiring are OK. If you measure zero ohms then you have a kill switch/wiring issue.
The other inputs your CDI needs to make spark are AC Ignition Power, and the Trigger signal. Do the following:
1) Unplug the CDI. In the wiring connector measure the resistance of the AC Ignition Power pin to the Ground pin. You should see 400 ohms or so. What do you measure?
2) Measure the resistance of the Timing/trigger pin to the ground pin. You should measure 150 ohms or so. What do you measure?
3) Leave the CDI unplugged. Set your meter to measure AC volts on the 100 volt scale. Measure the voltage on the AC Ignition Power pin to the ground pin while cranking the engine. You should see 40 to 80 volts AC while the engine is cranking. What do you measure?
4) Set your meter to measure AC volts on the lowest scale you have. Ideally this would be 2 volts but many meters don't go down this low. In that case use the lowest scale you have. Measure the voltage on the Timing Trigger pin to the Ground pin while cranking the engine. You should 0.2 t0 0.4 volts AC. What do you measure?
Now for measuring the output side of the CDI:
A) Leave the CDI unplugged. In the CDI wiring connector measure the resistance of the Ignition Coil pin to the ground pin. You should measure less than 1 ohm (but not zero ohms). What do you measure?
B) Plug the CDI back in. Set your meter to measure AC volts on the 20 volt scale. Set all kill switches to the run position. Crank the engine while measuring the voltage on the Igntition Coil pin to ground. Poke through the insulation of the wire if you can't probe the connector.
Caution: There should be moderately high voltage spikes on this wire. Make sure your fingers are not part of the circuitry. Don't touch the probe lead tips while doing this test.
What you should see is a lot of random numbers with lots of zero values as well. This is because the meter may catch all or part of the spark event voltage, with a lot of nothing in between. Describe what you see.
Note: Using a meter to measure this point produces highly variable results depending on the meter. What you really need is an oscilloscope, but most always a meter is all that is available. We have to do the best we can with what's available. Describe the meter results as accurately as you can - there is information there to chew on....