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Yamoto 150cc no spark

Ran when I bought it last week, was a little noisy which I found to be the stator had come loose and sheared the bolts, replaced but now have no spark have tried cdi and coil my original cdi has a green plug on with 6 pins but 2 centre ones have been removed, but new cdi has all 6 pins, red black wire was not originally connected to cdi I think it it just had a 12v to it would that be right? Any help appreciated

I don't know what you mean by "but 2 centre ones have been removed". I looking at a mental picture of a 6 pin CDI and cannot see any of them as being unambiguously in the center. So which pins have been removed exactly?

I also don't know what you mean when you say the "red/blk wire was not originally connected". Red/blk is usually power to the CDI, and it can be either 12 volts DC (for a DC powered CDI), or moderately high voltage AC (for an AC powered CDI). But if it wasn't originally connected how could it possibly work? You're leaving out major pieces of the puzzle in your description...;).

Here is a generic procedure for determining if you chinese 4 stroke 6 pin CDI quad is DC powered or AC powered:

Quote:

The 2 plug 6 wire CDIs come in two different designs. One is powered off 12 volts DC, and the other is powered off a moderately high voltage AC which comes from the stator. Unfortunately there is no reliable way to tell the difference between the two by just looking at them. To be sure you need to use a meter to find out which you have:
http://i397.photobucket.com/albums/p...CDI_Pinout.jpg
1) Unplug the CDI, and turn on the ignition. Do not crank the starter motor. Use a meter to measure the *DC* voltage on the pin labeled "AC ignition power" in the wiring harness to both ground pins in the 4 pin CDI connector. If you measure 12 volts DC then you have a DC powered CDI.

2) If you don't measure 12 volts DC on the ignition power pin, then switch the meter over to measure AC volts on the 200 volt scale. While cranking the starter motor, measure the AC voltage on the "AC Ignition Power" pin to the the Ground pin. You should see 40 to 80 volts AC. If you measure AC voltage when the starter is turning then you have an AC powered CDI.

Using a meter is the only 100% reliable way to figure out if your CDI is AC or DC powered. But there are some clues you can use that are usually (but not always) correct:

A) DC CDIs tend to be a little larger than their AC powered counterpart. This is because the DC powered CDI needs a bunch more circuitry to convert the 12 volts DC to the moderately high voltage supply that all CDIs must have.

B) Most (but not all) DC powered quad ignition systems do not use the kill switch input pin. The CDI connector pin usually has no wire tied to it. AC powered quad ignition systems usually do use the kill switch input pin.

Once that detail is established, the next step to figure out why you don't have spark. But the procedure for that is different depending on whether your CDi is AC or DC powered...:).

thanks for your reply,hoped you would reply as found a lot of your info in other posts helpful over the weekend, this is the same as my original cdi,
Attachment 16943
the red/black wire from stator was just taped up in the loom we believe, and cdi just had a 12v power when ignition on, so thought the new cdi might be ac and old one dc is that an issue?
new cdi has same plug as this
Attachment 16944
so followed one of your wiring diagrams at the weekend and hooked everything up with the cdi disconnected measuring loom plug we have 96.2vac coming up the red/black wire when cranking
blue/white trigger wire 0.01/0.02 constant when cranking although i had read this should be a pulse?
tried with kill switch hooked up and disconnected, and ignored top row centre pin,
with cdi plugged in we have a drop in power to 72vac coming to cdi and going to coil this is also same reading at the end of plug lead but doesnt spark, have tried 2 coils
do i need to go back to using a dc cdi exactly the same as before and not use red/black wire (stator output)
or do i have the wrong stator

My comments embedded in blue:

Quote:

Originally Posted by Jonesyscoob (Post 3058990)

thanks for your reply,hoped you would reply as found a lot of your info in other posts helpful over the weekend, this is the same as my original cdi,
[picture snipped]
[This is the first time I have seen a four pin DC powered CDI on a 150cc quad. Normally these have the 6 pin CDI (2 connectors - 2 pin and 4 pin)]
the red/black wire from stator was just taped up in the loom we believe, and cdi just had a 12v power when ignition on, so thought the new cdi might be ac and old one dc is that an issue?
new cdi has same plug as this
[picture snipped]
[I've not seen a CDI with this connector at all. It is entirely possible that the new CDI is AC powered. Where did you get this CDI? Is there any link you can provide so I can take a look? Was this CDI specified for 150cc quads?]
so followed one of your wiring diagrams at the weekend and hooked everything up with the cdi disconnected measuring loom plug we have 96.2vac coming up the red/black wire when cranking [Definately AC power for an AC powered CDI. But it is also possible that it was folded back up into the wiring harness because the quad wiring was modified to work with a DC powered CDI]
blue/white trigger wire 0.01/0.02 constant when cranking although i had read this should be a pulse? [10 to 20 millivolts (0.01 to 0.02 volts) is not right. Measure the resistance of this wire to ground. What do you get? It should be about 150 ohms. Try going down to the stator connections where they come out of the engine. Disconnect the blue/white wire there. Measure the resistance again from that same wire to ground looking into the engine. What do you measure here? Sometimes on DC powered CDIs the kill switch is wired in so that it shorts this wire to ground to kill spark. Thus I wondering if you just have a kill switch issue.]
tried with kill switch hooked up and disconnected, and ignored top row centre pin,
with cdi plugged in we have a drop in power to 72vac coming to cdi and going to coil this is also same reading at the end of plug lead but doesnt spark, have tried 2 coils [Plugging the CDI and stator AC power together gives meaningless results. The CDI yanks the stator voltage around even under normal circumstances. Even if the voltage drop is abnormal (which it isn't) there is no way to tell is the CDI is yanking too hard or the stator is buckling under normal load. That is why the measurements are made with the CDI disconnected. But I don't understand the part about the coil measuring the same. Those voltages should not be related in any way. Please check that again. This does not make any sense because if you have no trigger voltage (as you reported above) the CDI wouldn't fire, and you would have no voltage at all at the coil input or the coil output. If you really do see a voltage here this would be an indicator of something really bizarre, so look carefully and report what you find with as much care and detail as you can.]
do i need to go back to using a dc cdi exactly the same as before and not use red/black wire (stator output) [ As long as you get the power wired up right (DC power for a DC CDI, and AC power for an AC powered CDI) they should otherwise both work. The trigger input requirements are the same, and the coil drive outputs are the same. The only wildcard here is the kill switch circuitry. Notice that the four pin CDI does not have a kill switch input, so the spark must be killed by other means. On four pin CDIs the only proper way to kill the spark is to remove DC power to the CDI, remove the ground to the CDI, disconnect the trigger signal to the CDI, or short the trigger signal going to the CDI to ground. When I say "proper way" I'm talking about good design. I've seen others post about adding a kill switch by shorting the input to the ignition coil to ground. This may work (for a while), but is bad design for a number of reasons, but some get away with it.]
or do i have the wrong stator

I have resistance of 142 on the trigger wire blue White, and on the red black 484, I think they have sent wrong cdi as it looks like a 50cc scooter one! Have tried new cdi today as in the pic you sent me with the 2 plugs although it looks as if the kill and input wires are the other way? Would the output to the coil be above the input from stator on the plug? New stator in again and still same readings, if i remove the spark plug and put test lead in there it is showing 80vac when cranking? Could flywheel be problem? No kill switches connected at the moment as we wanted to eliminate them and just focus on getting the spark back. So if I put a 4 pin cdi back in am I right to just tape the red black stator wire up and not use, and feed the dc pin from ignition 12v? Or should I still be using that wire to run cdi

Attachment 16937
this is wiring to new cdi unit when cranking there is 80 vac coming from the black white wire? is that right as i thought that should be the kill switch wire? there is no voltage on the black yellow wire?

In blue again...

Quote:

Originally Posted by Jonesyscoob (Post 3059456)

I have resistance of 142 on the trigger wire blue White [OK], and on the red black 484 [OK], I think they have sent wrong cdi as it looks like a 50cc scooter one! Have tried new cdi today as in the pic you sent me with the 2 plugs although it looks as if the kill and input wires are the other way? Would the output to the coil be above the input from stator on the plug? [I've highlighted the previous statement in red because it is completely contradictory to what you say in your next post (with the pictures) - i.e: "there is no voltage on the black yellow wire". But the black yellow wire *is* the output from the CDI to the coil. I'm confused. The output to the coil from the CDI has high voltage in this post, and it has no volts in the next. Something is not right here ;). ] New stator in again and still same readings, if i remove the spark plug and put test lead in there it is showing 80vac when cranking? [Measuring the input voltage to the coil (which is the output from the CDI) is OK. It is always less than a few hundred volts at any engine speed. But trying to measure the spark plug voltage while cranking the engine coming out of the ignition coil high tension wire to the spark plug should never, ever be done. That is a really good way to destroy a meter. A working coil secondary winding into a high impedance like a meter could generate tens of thousands of volts. Even though they try to design meters to have some protection against high voltage transients, it is not a good idea to ever subject your meter to anything like that. Note, it is OK the measure things like ohms on the secondary side of the coil while the engine is stopped. No high voltage is generated with the engine stopped.

Now back to the 80 volts AC... I have to assume you are measuring this voltage on the input to the coil (the coil primary, or the yellow black wire from the CDI). I don't know since it depends on which post I read. What are you using as a ground for your meter? Are you using the green wire at the CDI, or are you using the engine chassis? I'm wondering if the ground wire to the CDI is open...

It is normal for the kill switch wire to have AC moderately high voltage on it when the CDI is connected up. Even though it is moderately high voltage it is current limited, and under normal operation when you short this line to ground it starves all the power to the CDI and the spark extinguishes.] Could flywheel be problem? No kill switches connected at the moment as we wanted to eliminate them and just focus on getting the spark back. So if I put a 4 pin cdi back in am I right to just tape the red black stator wire up and not use, and feed the dc pin from ignition 12v? Or should I still be using that wire to run cdi

Is the CDI getting triggered or not? You reported 10 to 20 millivolts AC from the trigger wire from the stator before. You have the correct resistance looking from the CDI to the trigger winding in the stator. 10 to 20 millivolts (0.01 to 0.02 volts AC) is not right. With this kind of voltage the CDI will not triggger, and you will measure zero voltage at the black yellow wire CDI output. So do you really have 10 to 20 millivolts AC trigger signal? Do you, or do you not have voltage on the yellow black wire to the coil? :confused:

No I don't think cdi is getting triggered as I still have the same readings onthis wire 0.01, so the power is getting to cdi on the red black wire but not coming out of the black/ yellow, I have used chassis and pin to ground when testing, what does ground wire open mean? Is it definitely black and yellow that is power to the coil from cdi as it is on the centre pin in my pic? Do you think flywheel is not sending the trigger? We literally have tried everything! And everything is re wired and only ignition key and start button are connected to eliminate everything else could this be a problem and need everything connected up?

Quote:

Originally Posted by Jonesyscoob (Post 3059560)

If the ground wire at the CDI connector (green wire) does not make it to all the other grounds (in other words the wire is open), then the CDI will not make spark. But if you measure your AC Ignition input voltage using just the ground and ignition power pins at the CDI connector (and not using engine ground as one of the meter probe points), then your ground wire to the CDI is fine. Another way to see that your ground wire is OK is to just measure it wth the ohmmeter on a realy low scale like 200 ohms. Measure the resistance from the ground pin on the CDI connector to engine ground. It should not be more than a couple ohms.

So currently there is plenty of AC power to the CDI, and there is no voltage on the yellow black wire from the CDI output to the ignition coil primary winding.

You don't have a trigger voltage sufficient to trigger the CDI (10 to 20 millivolts AC). And your trigger coil resistance is within reasonable values.

You had stator trouble with sheared bolts.

Look at your trigger signal pickup coil mounted outside the flywheel. Look for a raised rectangular bump on the flywheel that passes under the trigger pickup coil. If you rotate the flywheel so that raised bump on the flywheel is under the trigger pickup coil, what is the gap clearance? This gap is important for proper trigger signal amplitude. It should be something like 0.025". If it is bigger than that you will get no trigger to the CDI at cranking speeds.

Else it is looking like you stator is bad based on the info above.

Ok checked ground resistance from ground pin to chassis on 200 scale and is 0.06, my other resistance readings that I posted earlier for trigger and ac input were on the 2000 scale is that ok?