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Post by mrfixit on Apr 6, 2014 17:55:01 GMT -5
Ok I am new to this site and posting on forms in general so bear with me. I am quite mechanicaly ept. A friend brought over ataotao 49cc scooter that would not run. After cleaning the carb and replacing the fuel lines and charging the battery I checked to see if it was getting spark. Spark ok (so i thought) Ti seamed to be out of time because it fired way before TDC. Checked valve timing, good, checked compression,good. Talked to local scooter shop said CDI, bought one, installed, same thing. This time I notaced that the plug is firing a contious spark not a spark pluse. Old CDI samething, The next scooter shop sold me new stator, samething. Decided to do more checking. unhooked the blue and white pickup coil wire, ha guess what, thats right, Sparkplug is glowing a continous spark. Now i am scratching my head and askinng if anyone has any ideas? I havebeen allover the web and have not seen any one with this issue.
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Post by ramblinman on Apr 6, 2014 18:54:18 GMT -5
i was going to suggest checking the pickup coil after you said you replaced the CDI. i don't know how to test though so may want to get more info before you go needlessly replacing parts.
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Post by jjoshua20213 on Apr 6, 2014 19:44:17 GMT -5
The pickup coil tells the cdi when to send spark to the spark plug. Its possible its damaged and sending signals at incorrect times. Mine did the same thing right before it died. Sounds just like timing is wrong. Misfiring, back firing, spudderiing.If your getting spark the stator is fine, but the trigger coil sounds bad.
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Post by mrfixit on Apr 6, 2014 19:48:45 GMT -5
The new stator came with the pickup coil and it is gaped properly in relation to the flywheel but i still get spark with the pickup removed! The check is the resistance about 180 ohms
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Post by mrfixit on Apr 6, 2014 19:59:42 GMT -5
Is it possible that the flywheel retained some magnetism from the permanent magnets inside and triggering the cdi?
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Post by tvnacman on Apr 6, 2014 20:12:24 GMT -5
I had a man order an 11poll stator upgrade kit . There was a problem with where the trigger magnet was , his scooter was a SYM . Can you post a picture of your magneto and the pointer when the cam shows tdc . I wonder if there is something with the magnetos pulse magnet .
John
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Post by tvnacman on Apr 6, 2014 20:19:29 GMT -5
I would check for pulse signal/voltage at the cdi with the pulse coil removed and the connector at the stator disconnected . If there is stray voltage from chafed wire that could be triggering the cdi to fire .
John
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Post by mrfixit on Apr 6, 2014 20:48:03 GMT -5
you are saying to remove the pickup coil and unplug it from the wiring harnes, then check if there is a voltage on the yellow and black wire going to coil. What kind of voltage should i expect?
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Post by jjoshua20213 on Apr 6, 2014 20:49:41 GMT -5
Something is interfering with the signals the pickup coil is sending to the cdi. Faulty wires?
You know how to set the camshaft at the right timimg right? You know how you use the flywheel to do it? The spark is set to fire when the piston is all the way out closest to the head it can get. Well at top dead center(When the piston is closest to the head) the bump on the outer flywheel should met up directly with the pick up coil. If you've confirmed than then you have bad wiring
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Post by alleyoop on Apr 6, 2014 20:53:41 GMT -5
Well here is the thing, HE did say it was firing WITH the pick up coil disconnected. So my thoughts are maybe the guy messed with the wiring and the CDI I would check where that trigger wire plugged into the CDI is coming from.
Alleyoop
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Post by mrfixit on Apr 6, 2014 21:06:10 GMT -5
Well I checked the voltage @ the cdi and am getting about 4 vac on the yellow and blue wire and about 40 vac on the black and red wire this with the pickup coil removed and yes there is a continous spark at plug
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Post by mrfixit on Apr 6, 2014 21:12:32 GMT -5
Oh yes I did check the timing with piston @ tdc with bump on flywheel under pickup and timing mark T at pointer on crankcase. All the holes on cam gear were where they are supposed to be.
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Post by alleyoop on Apr 6, 2014 21:28:03 GMT -5
Follow the trigger wire plugged into the CDI and see where it is coming from. That wire has to be getting juice from other than the PICK UP COIL.
Alleyoop
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Post by justbuggin2 on Apr 6, 2014 21:30:17 GMT -5
I will go along the same lines as Alley sounds to me you have a wiring problem with a short in the wires going to the CDI
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Post by mrfixit on Apr 6, 2014 22:02:25 GMT -5
Ok I dont know the pin out on the cdi but have checked the wires and they are all good. and yes allyoop I know that I dont know, but the more i know, the more i know that i dont know. Thanks, will look up the proper pin out and follow the wires.
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..BAD TO THE BONE..
