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Post by lostforawhile on Aug 15, 2017 18:35:10 GMT -5
Ok this is the third bad CDI I have gotten, one from ebay, two from amazon, three different sellers, the bike runs fine on the stock one, This is supposed to be a spare, but all three have been dead out of the water, I have also noticed after swapping back to the stock CDI it takes a lot of cranking to get it to start again, when normally it starts right up. Are there this many bad ones floating around? this is just a stock AC CDI for a 139 QMB , nothing special
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Post by gsx600racer on Aug 15, 2017 19:01:50 GMT -5
I think that 3 dead cdi's in a row from different sellers would be very rare. If your luck is that bad, I am not standing next to you in a electrical storm.  Just for the record, Iv owned a 139qmb with a DC cdi.(so not all 139qmb's are AC) My guess is maybe its a cdi thats specific/special to your scooter or it could be DC. Whats is the scooter make and model ? |
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Post by lostforawhile on Aug 15, 2017 19:07:57 GMT -5
I think that 3 dead cdi's in a row from different sellers would be very rare. If your luck is that bad, I am not standing next to you in a electrical storm. Just for the record, Iv owned a 139qmb with a DC cdi.(so not all 139qmb's are AC) My guess is maybe its a cdi thats specific/special to your scooter or it could be DC. Whats is the scooter make and model ? it's a 2016 Yiben I have no idea on the model as the dealer left off the decals, but the numbers on the CDI come back to a generic CDI for a 139 QMB, it's definitely not DC as the boxes are a lot larger , and no you don't want to stand next to me in an electrical storm, I've been nearly hit by lightning 9 times |
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Post by lostforawhile on Aug 15, 2017 19:12:35 GMT -5
the only numbers on it are FLP YNF which searches to stock AC cdis
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Post by lostforawhile on Aug 15, 2017 19:15:31 GMT -5
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Dogbite
Scoot Member
Chinese scooter Hacker
Posts: 48 
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Post by Dogbite on Aug 15, 2017 20:43:57 GMT -5
I have seen stock bikes that eat performance cdi's in about a minute,they are fragile compared to stock. Some bikes seem to put out a ridiculous amount of ac from the stator like 100 volts. Check you ac voltage going into your cdi from the black and red wire by disconnecting the 2 pin on cdi and cranking the bike over.Then check ac voltage at the back of the coil black and yellow wire.
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Post by lostforawhile on Aug 15, 2017 20:51:05 GMT -5
I have seen stock bikes that eat performance cdi's in about a minute,they are fragile compared to stock. Some bikes seem to put out a ridiculous amount of ac from the stator like 100 volts. Check you ac voltage going into your cdi from the black and red wire by disconnecting the 2 pin on cdi and cranking the bike over.Then check ac voltage at the back of the coil black and yellow wire. I'll check it tomorrow, it won't even start on the aftermarket ones, what's strange is the bike refusing to crank for a long time, after reconnecting the stock one, I ordered a stock looking one from Amazon, I had a credit, I've got a long trip in November, so getting spares together |
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Post by gsx600racer on Aug 16, 2017 11:23:35 GMT -5
I did a little searching for your year and make scooter and couldn't find much. Iv bought at least a half dozen cdi's in the past, ac & dc for both 2 and 4 stroke scooters and never had an issue with them not working out of the box.
I wish I had a better answer for ya. 3 in a row that don't work but the stock one does work has me stumped.
Keep us posted.
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Post by FrankenMech on Aug 16, 2017 20:06:03 GMT -5
gsx600racer, I wish you would get rid of that avatar. I have done the face plant all too many times just walking. My left leg gives out. Seeing it over and over is gut wrenching. I can feel my hands sliding over the concrete, flesh grinding away, pebbles etc embedding into the flesh, trying to avoid the inevitable face plant impact and more flesh and bone grinding away   |
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Post by greginisn on Aug 18, 2017 23:23:20 GMT -5
Lost,
Were you able to return the faulty CDIs?
NYC parts people say all their stuff is tested, have you tried them or bought one for a Genuine Buddy? They might be made better than the average Chinese unit.
Greg
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Post by lostforawhile on Aug 19, 2017 17:56:47 GMT -5
Lost, Were you able to return the faulty CDIs? NYC parts people say all their stuff is tested, have you tried them or bought one for a Genuine Buddy? They might be made better than the average Chinese unit. Greg I was refunded for the last one and told to keep it, if someone wants to try it, my guess is these performance CDIs have a high advance curve, and it won't allow the bike to start, the best scenario is actually a little bit of retard for starting, I just got a stock replacement and I haven't been able to try it yet, a good CDI will advance the timing on a curve, not all at one time, some regular non scooter bikes, the CDI senses the voltage at the starter solonoid and retards the ignition on startup , the other possibility is on these CDIs, the dc voltage that dumps from the capacitor to the coil, may be reversed for some reason, or the wiring on the bike is deliberately reversed at the coil, does someone have a good pinout of the standard 6 pin cdi? I want to see if positive and negative are reversed to the coil , it wouldn't seem like it would make much difference but a coil wired backwards has a very weak spark |
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Post by lostforawhile on Aug 19, 2017 18:15:06 GMT -5
All these pinouts say AC to the coil, but the capacitor can't output AC, only part of the waveform as DC, it charges with AC though,
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Post by gsx600racer on Aug 19, 2017 18:39:20 GMT -5
Disconnect the CDI from the wiring harness. Take a meter and set it to DC. Ground the black lead to the frame or something that you know is ground(negative side of battery is best). Turn the key to ON(engine not running for obvious reasons). Take the RED lead and check every pin on the harness for voltage. If you find voltage, its a DC cdi. If you get nothing on all the pins its a AC cdi.
A DC CDI gets its power from the battery to charge the CDI to fire the coil.
A AC CDI gets its power for the exciter coil on the stater, the engine needs to be rotating to do this. AC power is made by the exciter coil to charge the CDI to fire the coil.
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Post by greginisn on Aug 19, 2017 19:29:21 GMT -5
Lost, maybe this a bit over kill but does this help? 
Greg |
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Post by lostforawhile on Aug 19, 2017 19:31:07 GMT -5
its definitely an AC for one thing the DC units are much larger, the last orange one I got is actually bigger then stock, so I wonder if they sent me a DC unit
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