KenMathisHD
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Since it doesn't appear to be out there already for this kart, here's a sort of basic write-up to test the ignition system on this thing. This is using my diagnosis results, the wiring diagram for this thing and the service manuals found by other members for other CF250/CN250 bikes. Hopefully, it'll help make it a bit easier for someone else when dealing with a no-spark on this type of kart/motor later. The ignition system for this is DC, not AC
CDI Pinout
1 - From trigger wire
2 - To ignition coil
3 - Ground
4 - Nothing
5 - Kill Switch
6 - DC Power from the ignition switch
View attachment 128145
Steps
1. Remove spark plug from the plug wire and check for spark using a spark tester. Set it to about the gap of your plug (I'm going by the gap recommended on the CFMOTO cover which says about 0.03-0.035), then attach one end to your coil wire, and the other end to ground. You can use the top of the cylinder head for ground, but use a multimeter before doing so to ensure the cylinder head is grounded to the battery. Once you're hooked up, crank the motor while looking at the spark tester. You're looking for a bright, strong spark. If you get spark at this point, your plug is likely bad or fouled out. If no spark, continue on.
2. Check resistance between the plug wire end and the green terminal (ground end) on your ignition coil. Without the plug cap, you should see somewhere between 3.6k-4.6k ohms. With the plug cap connected, I see about 8.46k ohms, so I'm figuring the plug cap end adds about 4k-5k ohms. If you're seeing much higher or lower than the values listed, your issue may lie with the coil or plug wire.
3. Check resistance between the two terminals on your ignition coil, you should see somewhere between 0.16-20 ohms. If you're seeing much higher or lower than the values listed, your issue may lie with the coil or plug wire.
4. Check for continuity between pin 2 of your CDI and the black terminal (power supply terminal from CDI) of your ignition coil. You should see a reading similar to if you were to touch the two prongs of your multimeter together. If no or low continuity, there's an issue with the wiring going from your CDI to your ignition coil.
5. Check to make sure the green (ground) terminal of your ignition coil has a good connection to ground. If no or low continuity, there's an issue with the wiring going from your ignition coil to ground.
6. Check for DC power going to CDI at pin 6 - you should be getting at least 12V. If you're not, your issue likely lies either with your ignition switch or the wiring going to/from it.
7. Check pin 3 for good ground to the motor and battery. If no or bad ground, you have a grounding issue.
8. Check to make sure pin 5 is not currently grounded out. This should only be a ground when your kill switch is active. If this is grounded out when your kill switch is not active, you likely either have a problem with your kill switch or the wiring leading to/from it. If you can, safely remove this pin from the connector while testing, but be sure to replace it in the connector afterwards. It's not a big deal if you can't remove it, just be sure that it isn't grounding out while you're testing your wiring.
9. Find the two wires coming from your exciter coil/trigger wire, one is green, one is blue. I found mine by pulling the buggy chairs out and looking at the wiring that is sort of below and to the left of the carb if you're looking at the mouth of the carb - they should be in the same area as the wires going from your stator to your voltage regulator/rectifier. Follow them up to their connector, disconnect them, and check the resistance between the two terminals. You should see anywhere between 50-350 ohms. If you're getting a reading much higher or lower than these values, your issue is likely the exciter/trigger coil.
10. If you want, you can also check for DC voltage at pin 1 while cranking, you should get a minimum of 0.01v while cranking. If you're getting at least that, your trigger signal is likely being sent. At this point, having ruled out the ignition coil, trigger coil, CDI power supply, CDI ground, and the kill switch, your issue is likely your CDI.
CDI Pinout
1 - From trigger wire
2 - To ignition coil
3 - Ground
4 - Nothing
5 - Kill Switch
6 - DC Power from the ignition switch
View attachment 128145
Steps
1. Remove spark plug from the plug wire and check for spark using a spark tester. Set it to about the gap of your plug (I'm going by the gap recommended on the CFMOTO cover which says about 0.03-0.035), then attach one end to your coil wire, and the other end to ground. You can use the top of the cylinder head for ground, but use a multimeter before doing so to ensure the cylinder head is grounded to the battery. Once you're hooked up, crank the motor while looking at the spark tester. You're looking for a bright, strong spark. If you get spark at this point, your plug is likely bad or fouled out. If no spark, continue on.
2. Check resistance between the plug wire end and the green terminal (ground end) on your ignition coil. Without the plug cap, you should see somewhere between 3.6k-4.6k ohms. With the plug cap connected, I see about 8.46k ohms, so I'm figuring the plug cap end adds about 4k-5k ohms. If you're seeing much higher or lower than the values listed, your issue may lie with the coil or plug wire.
3. Check resistance between the two terminals on your ignition coil, you should see somewhere between 0.16-20 ohms. If you're seeing much higher or lower than the values listed, your issue may lie with the coil or plug wire.
4. Check for continuity between pin 2 of your CDI and the black terminal (power supply terminal from CDI) of your ignition coil. You should see a reading similar to if you were to touch the two prongs of your multimeter together. If no or low continuity, there's an issue with the wiring going from your CDI to your ignition coil.
5. Check to make sure the green (ground) terminal of your ignition coil has a good connection to ground. If no or low continuity, there's an issue with the wiring going from your ignition coil to ground.
6. Check for DC power going to CDI at pin 6 - you should be getting at least 12V. If you're not, your issue likely lies either with your ignition switch or the wiring going to/from it.
7. Check pin 3 for good ground to the motor and battery. If no or bad ground, you have a grounding issue.
8. Check to make sure pin 5 is not currently grounded out. This should only be a ground when your kill switch is active. If this is grounded out when your kill switch is not active, you likely either have a problem with your kill switch or the wiring leading to/from it. If you can, safely remove this pin from the connector while testing, but be sure to replace it in the connector afterwards. It's not a big deal if you can't remove it, just be sure that it isn't grounding out while you're testing your wiring.
9. Find the two wires coming from your exciter coil/trigger wire, one is green, one is blue. I found mine by pulling the buggy chairs out and looking at the wiring that is sort of below and to the left of the carb if you're looking at the mouth of the carb - they should be in the same area as the wires going from your stator to your voltage regulator/rectifier. Follow them up to their connector, disconnect them, and check the resistance between the two terminals. You should see anywhere between 50-350 ohms. If you're getting a reading much higher or lower than these values, your issue is likely the exciter/trigger coil.
10. If you want, you can also check for DC voltage at pin 1 while cranking, you should get a minimum of 0.01v while cranking. If you're getting at least that, your trigger signal is likely being sent. At this point, having ruled out the ignition coil, trigger coil, CDI power supply, CDI ground, and the kill switch, your issue is likely your CDI.
