Lynn,
My In-laws gave me this atv, ZHEJIANG Easy Vehicle Co. The wiring is a mess on it. I have been reading your threads for testing the stator and CDI. It has the 5 pin CDI and here are the results i got.
Power pin- 51 vac, 616 ohms
Trigger pin- 0.1 vac, 119 ohms
Ground- 0 ohms
Any thoughts?

 

Disconnect the kill switch wire at the CDI. With a small screwdriver you can press in the locking tab on the pin and extract it.

Got spark now? Be aware that if you do this with the plug installed in the cylinder, and the quad starts up, you will have no good way to shut the quad down. In this situation you will need to turn off the ignition first (this is important), then reinsert the wire with insulated pliers to the CDI to kill the ignition. The kill switch pin from the CDI has high voltage on it whenever the engine is spinning so mind you fingers accordingly.

Your trigger voltage sound a little low, but may be OK depending on your meter. Measure the AC voltage at the ignition coil pin of the CDI while cranking and all kill switches set to the run position. Watch it for 10 seconds of cranking and describe in detail what you see with the meter. What I'm trying to do is determine if your CDI is getting triggered at all. Meters aren't designed to measure this kind of waveform and different meters do it differently. Detail is key.

 

I disconnected the kill switch, no spark.
Coil- flucuates 0.1-0.3 vac for 10 sec.

 

This is one of those situations where nothing is cut and dry, and that makes it a little tougher. Meters don't do well measuring the trigger voltage or the coil voltage. Different meters read differently. It is not the tool of choice (an oscilloscope would be the right tool), but meters are usually all that are available. Your meter readings are very ambiguous. Sometimes that happens.

Let's try some things:

1) Measure the cdi output pin resistance to ground. This will probably be a low resistance, but it shouldn't be zero.

2) Measure the resistance from the spark plug wire to ground. What do your measure?

3) And remeasure your coil voltage out of the CDI (CDI plugged in and all kill switches in the run position). Make sure it is the same. Then short the timing trigger pin to ground while repeating the test. Do you see any change in the CDI output voltage?

I'm fishing for clues. The trigger voltage is low, but it is not zero. Is your CDI getting triggered? I don't know yet. To determine that we look at the CDI output and see that it too is low, but still not zero. So if you short the trigger to ground the CDI definitely should not fire, and the CDI output should be something very close to zero volts. If the CDI output voltage changes when shorting the trigger to ground that tells me the CDI is getting triggered. If it doesn't change then it suggest the CDI isn't getting triggered.

 

1)I get no reading on any scale (not zero)
2)No reading when connected to coil. 4.87 ohm on 20K scale from cap through wire not connected to coil.
3)Coil pin as high as 12vac dropping to 0.2-0.3vac. no change with trigger grounded.

I was talking to a local dealer and I can get the coil for $20 as well as the 4pin CDI for $20. Do you think I should just replace them both? Any way to test the trigger?

Thanks.

 

Oops, my instructions were not clear. Sorry. I should have said measure the CDI Output pin resistance in the wiring harness to ground (not the CDI itself). What this does is measure the resistance of the ignition coil primary and all the wiring to and from the coil primary. It should be a very low resistance (but not zero ohms).

I'm not understanding this. What you should be doing is measuring resistance from the plug clip inside the spark plug boot to engine ground (though the coil secondary winding). I'm not sure what you're doing different when you get 4.87K ohms versus "no reading".

But now things are different. Before you got only 0.1 to 0.3 volts AC, and now you are getting occasional spikes up to 12 volts AC. This is a completely different picture now. The voltage spikes suggest that the CDI *is* being triggered. Before the spikeless output suggested that the CDI was not getting triggered. If you do this test several times and you get the spikey results (with lots of near zero volts inbetween) then that points more the the coil as being the problem.

But then I was crestfallen when I read the next sentence where there was no change with the trigger pin shorted to ground. With no trigger there should be no moving voltages at the output of the CDI. This makes no sense. Are you *sure* there was no change when the trigger signal was shorted to ground?

I don't see a problem with a $20 coil. You can get them cheaper on eBay, but you have to wait for shipping. A four pin CDI will not work in your case. 4 pin CDIs are DC powered, while your is AC powered. Stay with 5 pin CDIs

 

I have 2 coils, I guess the privous owner had replaced it and the old one was in the trunk.

1)Still no reading(zero on second coil)
2)No reading again( I get 4ohms on second coil)
3)I noticed when doing this test, that when I release the start button the voltage jumps up high(maybe the meter trying to give the fluctating reading?)

The 4.87K was the reading I got when I tested the plug wire not connected to the coil through the cap.

 

I'm running a bit behind in my posts. I apologize for that - long work hours and I've got family visiting.

1) Both of those readings are wrong. You should get a low resistance like 0.3 ohms, but it should not be zero or open. Both coils (by your measurements are bad).

2) Again both of those readings are suspect. Open (I assume that is what you mean by "no reading") is definately wrong, and 4 ohms is less than I've ever seen reported. 12 ohms is the minimum I've seen. My coil has an integral resistor built into the secondary and measure about 8000 ohms (0.8 KOhms). BTW, there is no such thing as "no reading" unless your meter is turned off . If it reads open that's a valid reading. If it reads shorted (0 ohms) that's a valid reading too.

3) As mentioned before, meters aren't designed to measure this kind of complicated waveform. Usually what you get is near zero AC volts with occasional spikes as the meter happens to capture the very narrow high voltage pulses from the CDI to the ignition coil. It's strange that you only get voltage spikes from the CDI output when the start button is released. Is this consistent? Every time?

 

please help i have just purchased a zhejiang yongkang easy vehicle from a friend but he has lost the spark plug does anyone know the code for it. the model is yf110 50cc engine number 152fsh i have searched the net but can not find any info

many thanks darren::