2004 cr125 no spark

Edited Date/Time 6/8/2023 6:25pm

I checked the holms on the stator they came back good, wondering if I don't have spark because I don't have the electronic servos cables hooked up to the power valve, would this cause no spark? I have everything plugged in, tried a new rectifier and old ones, two different coils, a different wiring harness and two cdi boxes. I tried two different servo motors just without the cables hooked into the cylinder. could this be caused by the motor being out of position. 

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6/8/2023 6:37pm
I checked the holms on the stator they came back good, wondering if I don't have spark because I don't have the electronic servos cables hooked...

I checked the holms on the stator they came back good, wondering if I don't have spark because I don't have the electronic servos cables hooked up to the power valve, would this cause no spark? I have everything plugged in, tried a new rectifier and old ones, two different coils, a different wiring harness and two cdi boxes. I tried two different servo motors just without the cables hooked into the cylinder. could this be caused by the motor being out of position. 

Plugging the servo in or not plugging it in will make no difference to the spark.

6/9/2023 11:00am

okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i have power going to the wire you plug into the coil but im not sure if it is enough to go through the coil,(still no spark) is there a number that i should get out of that wire that you plug into the coil and if so what should it be. 

6/9/2023 11:00am
I checked the holms on the stator they came back good, wondering if I don't have spark because I don't have the electronic servos cables hooked...

I checked the holms on the stator they came back good, wondering if I don't have spark because I don't have the electronic servos cables hooked up to the power valve, would this cause no spark? I have everything plugged in, tried a new rectifier and old ones, two different coils, a different wiring harness and two cdi boxes. I tried two different servo motors just without the cables hooked into the cylinder. could this be caused by the motor being out of position. 

Plugging the servo in or not plugging it in will make no difference to the spark.

okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i have power going to the wire you plug into the coil but im not sure if it is enough to go through the coil,(still no spark) is there a number that i should get out of that wire that you plug into the coil and if so what should it be. 

6/9/2023 6:36pm Edited Date/Time 6/9/2023 9:13pm
okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i...

okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i have power going to the wire you plug into the coil but im not sure if it is enough to go through the coil,(still no spark) is there a number that i should get out of that wire that you plug into the coil and if so what should it be. 

Numbers will be in the Honda Service Manual...

https://www.helminc.com/helm/Result.asp?Style=helm&Mfg=AHC&Make=AHC&Model=CR02&Year=2004&Category=1&Keyword=&Module=&selected%5Fmedia=

They should be similar to earlier year CR125's...

image-20230610113149-1

Check the wires going to the ECU, the wires bend as they enter the ECU's plug, it is common for the wires to break there.

Check for continuity between the coil ground and the cylinder head, corrosion between the frame and engine can affect spark.

 

The Shop

6/9/2023 9:43pm
okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i...

okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i have power going to the wire you plug into the coil but im not sure if it is enough to go through the coil,(still no spark) is there a number that i should get out of that wire that you plug into the coil and if so what should it be. 

Numbers will be in the Honda Service Manual... https://www.helminc.com/helm/Result.asp?Style=helm&Mfg=AHC&Make=AHC&Model=CR02&Year=2004&Category=1&Keyword=&Module=&selected%5Fmedia= They should be similar to earlier year CR125's... Check the wires going to the ECU, the wires...

Numbers will be in the Honda Service Manual...

https://www.helminc.com/helm/Result.asp?Style=helm&Mfg=AHC&Make=AHC&Model=CR02&Year=2004&Category=1&Keyword=&Module=&selected%5Fmedia=

They should be similar to earlier year CR125's...

image-20230610113149-1

Check the wires going to the ECU, the wires bend as they enter the ECU's plug, it is common for the wires to break there.

Check for continuity between the coil ground and the cylinder head, corrosion between the frame and engine can affect spark.

 

i just powedercoated the frame and cerakoted the engine, i grinded the powder off where the engine comes in contact with it but do i need to grind the cerakote off as well, i still get power going to the wire that plugs into the coil i just cant get anything when i plug it in and try to get spark grounding it to the engine and the ground where the coil is on the frame. Could this be a grounding issue?

6/9/2023 10:31pm
i just powedercoated the frame and cerakoted the engine, i grinded the powder off where the engine comes in contact with it but do i need...

i just powedercoated the frame and cerakoted the engine, i grinded the powder off where the engine comes in contact with it but do i need to grind the cerakote off as well, i still get power going to the wire that plugs into the coil i just cant get anything when i plug it in and try to get spark grounding it to the engine and the ground where the coil is on the frame. Could this be a grounding issue?

It does sound like a grounding issue, measure continuity with a multimeter between the coil ground and the cylinder head, you may need to grind the cerakote off, or run a ground wire from the coil ground to the cylinder, this is what HRC did...

image-20230610152757-1

6/10/2023 7:47pm
okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i...

okay so i have spark on another bike with the same stator cdi box recifier and coil, i put all that on another bike and i have power going to the wire you plug into the coil but im not sure if it is enough to go through the coil,(still no spark) is there a number that i should get out of that wire that you plug into the coil and if so what should it be. 

Numbers will be in the Honda Service Manual... https://www.helminc.com/helm/Result.asp?Style=helm&Mfg=AHC&Make=AHC&Model=CR02&Year=2004&Category=1&Keyword=&Module=&selected%5Fmedia= They should be similar to earlier year CR125's... Check the wires going to the ECU, the wires...

Numbers will be in the Honda Service Manual...

https://www.helminc.com/helm/Result.asp?Style=helm&Mfg=AHC&Make=AHC&Model=CR02&Year=2004&Category=1&Keyword=&Module=&selected%5Fmedia=

They should be similar to earlier year CR125's...

image-20230610113149-1

Check the wires going to the ECU, the wires bend as they enter the ECU's plug, it is common for the wires to break there.

Check for continuity between the coil ground and the cylinder head, corrosion between the frame and engine can affect spark.

 

i just powedercoated the frame and cerakoted the engine, i grinded the powder off where the engine comes in contact with it but do i need...

i just powedercoated the frame and cerakoted the engine, i grinded the powder off where the engine comes in contact with it but do i need to grind the cerakote off as well, i still get power going to the wire that plugs into the coil i just cant get anything when i plug it in and try to get spark grounding it to the engine and the ground where the coil is on the frame. Could this be a grounding issue?

Not sure but I would ground the mount for the coil to bare aluminum.  Ps 04 125 like new coils.  Not made anymore & hard to find. But a ikat works great on these.  Good Luck

1
6/11/2023 2:07pm
i just powedercoated the frame and cerakoted the engine, i grinded the powder off where the engine comes in contact with it but do i need...

i just powedercoated the frame and cerakoted the engine, i grinded the powder off where the engine comes in contact with it but do i need to grind the cerakote off as well, i still get power going to the wire that plugs into the coil i just cant get anything when i plug it in and try to get spark grounding it to the engine and the ground where the coil is on the frame. Could this be a grounding issue?

It does sound like a grounding issue, measure continuity with a multimeter between the coil ground and the cylinder head, you may need to grind the...

It does sound like a grounding issue, measure continuity with a multimeter between the coil ground and the cylinder head, you may need to grind the cerakote off, or run a ground wire from the coil ground to the cylinder, this is what HRC did...

image-20230610152757-1

image 28.jpg?VersionId=47S7mPaMbYEvhkm8tliKtH2

I just need to know what I’m supposed to be getting out or this wire that plugs into the coil, I’ve tested the coil it comes out good, and mind you everything on this bike just came off another one with spark, it has a good ground tested it with a multi meter. This wire is getting power but I don’t know if it’s enough to fire the coil or not, I’ve tried different coils, rectifier and a different cdi and still nothing 

6/11/2023 6:06pm
I just need to know what I’m supposed to be getting out or this wire that plugs into the coil, I’ve tested the coil it comes...

image 28.jpg?VersionId=47S7mPaMbYEvhkm8tliKtH2

I just need to know what I’m supposed to be getting out or this wire that plugs into the coil, I’ve tested the coil it comes out good, and mind you everything on this bike just came off another one with spark, it has a good ground tested it with a multi meter. This wire is getting power but I don’t know if it’s enough to fire the coil or not, I’ve tried different coils, rectifier and a different cdi and still nothing 

100V minimum, but you should plug it in and test it at the coil...

image-20230612110359-1

image-20230612110605-2

cmang63
Posts
2
Joined
4/19/2024
Location
St. James, NY US
Fantasy
4452nd
4/19/2024 5:29pm

looking for some advice , i have a 2004 cr 125 i fully restored and once fully put back together i have no spark. I tested all components with multi meter for peak voltage and resistance. All came back good. Regardless i replaced the ignition coil, spark plug and kill switch with brand new OEM as well as tried another wiring harness. Still no spark. Im leaning towards it being a bad cdi ( mine has been roughed up a bit on bottom right corner but not cracked) however due to the fact that the 04 is a 1 off year they are expensive and hard to find. However i do have plenty of voltage at the black and yellow connector that the ignition coil plugs into but once ignition coil is plugged in I lose all voltage and multimeter reads 0. Is this a indication of a bad CDI or a grounding issue? The frame is not powder coated and I took a buffing wheel to the attachment points. As far as I am aware of the only 2 grounding wires on this bike is done through kill switch and the wire coming off the harness that connects along with the ignition coil, do i need to add another ground wire like pictured above? I do not recall the bike having one prior to disassembly but i could be forgetting. Any help is much appreciated as i would hate to spend close to 500 on a used cdi for just a grounding issue.

4/19/2024 7:54pm
cmang63 wrote:
looking for some advice , i have a 2004 cr 125 i fully restored and once fully put back together i have no spark. I tested...

looking for some advice , i have a 2004 cr 125 i fully restored and once fully put back together i have no spark. I tested all components with multi meter for peak voltage and resistance. All came back good. Regardless i replaced the ignition coil, spark plug and kill switch with brand new OEM as well as tried another wiring harness. Still no spark. Im leaning towards it being a bad cdi ( mine has been roughed up a bit on bottom right corner but not cracked) however due to the fact that the 04 is a 1 off year they are expensive and hard to find. However i do have plenty of voltage at the black and yellow connector that the ignition coil plugs into but once ignition coil is plugged in I lose all voltage and multimeter reads 0. Is this a indication of a bad CDI or a grounding issue? The frame is not powder coated and I took a buffing wheel to the attachment points. As far as I am aware of the only 2 grounding wires on this bike is done through kill switch and the wire coming off the harness that connects along with the ignition coil, do i need to add another ground wire like pictured above? I do not recall the bike having one prior to disassembly but i could be forgetting. Any help is much appreciated as i would hate to spend close to 500 on a used cdi for just a grounding issue.

Use your multimeter to check resistance between the ignition coil ground (green wire)...

image-20240420124745-2

and the spark plug ground (metal part of body)...

image-20240420124359-1

It should be a couple on ohms, if it's hundreds or thousands of ohms, there is a ground issue.

Check the wires going into the CDI, the wires have a sharp bend before entering the connector, the wires commonly break at the bend or disconnect from the crimped fitting inside the connector.

cmang63
Posts
2
Joined
4/19/2024
Location
St. James, NY US
Fantasy
4452nd
4/20/2024 12:42pm
cmang63 wrote:
looking for some advice , i have a 2004 cr 125 i fully restored and once fully put back together i have no spark. I tested...

looking for some advice , i have a 2004 cr 125 i fully restored and once fully put back together i have no spark. I tested all components with multi meter for peak voltage and resistance. All came back good. Regardless i replaced the ignition coil, spark plug and kill switch with brand new OEM as well as tried another wiring harness. Still no spark. Im leaning towards it being a bad cdi ( mine has been roughed up a bit on bottom right corner but not cracked) however due to the fact that the 04 is a 1 off year they are expensive and hard to find. However i do have plenty of voltage at the black and yellow connector that the ignition coil plugs into but once ignition coil is plugged in I lose all voltage and multimeter reads 0. Is this a indication of a bad CDI or a grounding issue? The frame is not powder coated and I took a buffing wheel to the attachment points. As far as I am aware of the only 2 grounding wires on this bike is done through kill switch and the wire coming off the harness that connects along with the ignition coil, do i need to add another ground wire like pictured above? I do not recall the bike having one prior to disassembly but i could be forgetting. Any help is much appreciated as i would hate to spend close to 500 on a used cdi for just a grounding issue.

Use your multimeter to check resistance between the ignition coil ground (green wire)... and the spark plug ground (metal part of body)... It should be a...

Use your multimeter to check resistance between the ignition coil ground (green wire)...

image-20240420124745-2

and the spark plug ground (metal part of body)...

image-20240420124359-1

It should be a couple on ohms, if it's hundreds or thousands of ohms, there is a ground issue.

Check the wires going into the CDI, the wires have a sharp bend before entering the connector, the wires commonly break at the bend or disconnect from the crimped fitting inside the connector.

Appreciate the response, i did as suggested and got some results. when testing for resistance from the ignition coil ground wire ( green wire) to the spark plug body when not connected to its mounting location my multi meter would auto adjust and display .931 m oms. I am assuming thats milliamps.  However when doing same test with the ground wire connected i would get 0.5 omns on average however it would sometimes spike close to 100 but always settle back down to the .5 to 1 omn range and the meter would not auto adjust and display the m symbol. I have 2 wiring harnesses and they both do not have any damage near the 8 pin and 4pin connectors and both have continuity between the connector and other plugs as suggested to test in honda owners manual. Would adding that addition ground wire help?

4/20/2024 7:52pm
cmang63 wrote:
looking for some advice , i have a 2004 cr 125 i fully restored and once fully put back together i have no spark. I tested...

looking for some advice , i have a 2004 cr 125 i fully restored and once fully put back together i have no spark. I tested all components with multi meter for peak voltage and resistance. All came back good. Regardless i replaced the ignition coil, spark plug and kill switch with brand new OEM as well as tried another wiring harness. Still no spark. Im leaning towards it being a bad cdi ( mine has been roughed up a bit on bottom right corner but not cracked) however due to the fact that the 04 is a 1 off year they are expensive and hard to find. However i do have plenty of voltage at the black and yellow connector that the ignition coil plugs into but once ignition coil is plugged in I lose all voltage and multimeter reads 0. Is this a indication of a bad CDI or a grounding issue? The frame is not powder coated and I took a buffing wheel to the attachment points. As far as I am aware of the only 2 grounding wires on this bike is done through kill switch and the wire coming off the harness that connects along with the ignition coil, do i need to add another ground wire like pictured above? I do not recall the bike having one prior to disassembly but i could be forgetting. Any help is much appreciated as i would hate to spend close to 500 on a used cdi for just a grounding issue.

Use your multimeter to check resistance between the ignition coil ground (green wire)... and the spark plug ground (metal part of body)... It should be a...

Use your multimeter to check resistance between the ignition coil ground (green wire)...

image-20240420124745-2

and the spark plug ground (metal part of body)...

image-20240420124359-1

It should be a couple on ohms, if it's hundreds or thousands of ohms, there is a ground issue.

Check the wires going into the CDI, the wires have a sharp bend before entering the connector, the wires commonly break at the bend or disconnect from the crimped fitting inside the connector.

cmang63 wrote:
Appreciate the response, i did as suggested and got some results. when testing for resistance from the ignition coil ground wire ( green wire) to the...

Appreciate the response, i did as suggested and got some results. when testing for resistance from the ignition coil ground wire ( green wire) to the spark plug body when not connected to its mounting location my multi meter would auto adjust and display .931 m oms. I am assuming thats milliamps.  However when doing same test with the ground wire connected i would get 0.5 omns on average however it would sometimes spike close to 100 but always settle back down to the .5 to 1 omn range and the meter would not auto adjust and display the m symbol. I have 2 wiring harnesses and they both do not have any damage near the 8 pin and 4pin connectors and both have continuity between the connector and other plugs as suggested to test in honda owners manual. Would adding that addition ground wire help?

0.5 to 1 ohm sounds good, you shouldn't need another ground wire.

Did you check the pulse generator?

image-20240421125142-1

The only other thing I can think of are the spark plug cap and the CDI.

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