Chinese Kit CDI Reverse Engineering

[UVsaturated]

So far, no ignition coil has been recovered from the depths of its epoxy-filled grave we call the CDI module, so we don't know any specifics about it, except for its secondary coil resistance.

Just for ****s and giggles, I might take you up on this challenge as I have some time, some abrasive files, and whatnot, and I'd like to see a replacement made for this.

I was enjoying the **** out of my bike until it quit working, now it will not fire. I've gone through the carb, checked everything, and it will not light. I am figuring that the electronics went to **** on the CDI and I would like to install a better one that is more reliable. I was thinking of finding a similar replacement that is sold off the shelf for an ATV or something like that.

Anyway, if I get to it, I will try to post something about it. I am without camera now, so have no way to post pics, but I would love to compare what I have with what you all have posted.

 

[rohmell]

Just for ****s and giggles, I might take you up on this challenge as I have some time, some abrasive files, and whatnot, and I'd like to see a replacement made for this.

I was enjoying the **** out of my bike until it quit working, now it will not fire. I've gone through the carb, checked everything, and it will not light. I am figuring that the electronics went to **** on the CDI and I would like to install a better one that is more reliable. I was thinking of finding a similar replacement that is sold off the shelf for an ATV or something like that.

Anyway, if I get to it, I will try to post something about it. I am without camera now, so have no way to post pics, but I would love to compare what I have with what you all have posted.

Yes, please join us in our quest to uncover the mysteries of the Chinese CDI Module.
The more people we have working on this project, the faster we can come to figuring out an alternative to the stock CDI unit.

 

[xxjrkkrjxx]

Yes, please join us in our quest to uncover the mysteries of the Chinese CDI Module.
The more people we have working on this project, the faster we can come to figuring out an alternative to the stock CDI unit.

Why can't we use a 50cc quad cdi box? Would that be an alternative? They use an external coil.I don't know too much about this stuff but I do know that the 2-stoke 50cc quad cdi boxes are dirt cheap. Take a look at this wiring diagram of the engine and electronics (www.onipse.com/Reid/wiring_diagram.gif) and this is the cdi I am talking about (www.onipse.com/Reid/50cc_cdi_box.jpg) I could be completely wrong about this even working. But just throwing ideas out there!

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[rohmell]

Why can't we use a 50cc quad cdi box? Would that be an alternative? They use an external coil.I don't know too much about this stuff but I do know that the 2-stoke 50cc quad cdi boxes are dirt cheap. Take a look at this wiring diagram of the engine and electronics (www.onipse.com/Reid/wiring_diagram.gif) and this is the cdi I am talking about (www.onipse.com/Reid/50cc_cdi_box.jpg) I could be completely wrong about this even working. But just throwing ideas out there!

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That CDI requires separate power and timing inputs. On the Chinese kit CDI, the power for the CDI and timing signal come in on the blue wire.

 

[CroMagnum]

That CDI requires separate power and timing inputs. On the Chinese kit CDI, the power for the CDI and timing signal come in on the blue wire.

rohmell is correct - there are all sorts of motorcycle CDIs on the market, including a ton of GY6 parts, but most require a 12v power source and a trigger coil.

But here's a wiring diagram out of a 2007 Yamaha PW80 service manual:

As you can see, no power source and no trigger coil. I think the PW80 CDI may just work on HT motors.

 

[rohmell]

The case style of that CDI is similar to the one used in the Yamaha DT-125, I wonder how different it is internally:

 

[CroMagnum]

It looks to me like that DT-125 CDI needs a trigger coil on the "Pickup" input, so it probably won't work.

 

[rohmell]

It looks to me like that DT-125 CDI needs a trigger coil on the "Pickup" input, so it probably won't work.

Yup, you are right about that...
If only I can find a schematic for the Yamaha PW80 CDI, then I will know for sure if it can be used, unless I can find one for sale cheap.

Interesting thing, though, all of the PW80 CDI pictures that I have seen so far show 7 wires on them, compared to your service manual wiring diagram of 5 wires.

 

[Ratchetbirds]

Note: Also posted in "roll your own CDI"


Couple other things to report. I read the ohms on the resistor on my board and at the lowest setting on my DVOM (20) it read 09.8. It is deffinately 1/2 watt sized. I have another cdi I can rip into. If anyone out there has a dead unit they want to send to me to be opened I would welcome them. Just PM me. The more we can examine the better. I still have a strong suspicion that moisture is what killed my CDI. I hope to find out tomorrow.

 

[rohmell]

Mr. Ratchetbirds,

Thanks for taking the time to revisit that PC board and take some readings, you have been a tremendous help in this project.
Is the glass diode on that board still intact?
If so, I am thinking that is is a Zener diode, and I can draw you a schematic that will allow you to determine its Zener voltage.

Spraying the CDI components with conformal coating or HumiSeal will protect against moisture, while still allowing easy inspection and repair of the CDI components.

 

[rohmell]

Mr. Ratchebirds,
Thank you for taking the time to revisit that board and take the resistance readings for the resistor.
You have been a tremendous help in this project.
Is the glass diode still intact?
If so, I am thinking that it is a Zener diode, and I can draw you a schematic that will allow you to determine its Zener voltage.

You can spray your CDI components with a conformal coating or HumiSeal.
That will protect the parts against moisture, while still being able to easily see and repair the CDI component parts.

 

[dakota47l1]

Microwave ovens still use a tube, a magnetron tube.

and guitar amps!!!tube amps are the best!

 

[rohmell]

and guitar amps!!!tube amps are the best!

Also, bicycle tires use tubes inside of 'em.

But, for real, military aircraft, such as the the MIG-25 still use tubes:
The majority of the on-board avionics were based on vacuum-tube technology, not solid-state electronics. Although they represented aging technology, vacuum tubes were more tolerant of temperature extremes, thereby removing the need for providing complex environmental controls inside the avionics bays. In addition, the vacuum tubes were easy to replace in remote northern airfields where sophisticated transistor parts might not have been readily available. With the use of vacuum tubes, the MiG-25P's original Smerch-A (Tornado, NATO reporting name "Foxfire") radar had enormous power – about 600 kilowatts. As with most Soviet aircraft, the MiG-25 was designed to be as rugged as possible. The use of vacuum tubes also makes the aircraft's systems resistant to an electromagnetic pulse, for example after a nuclear blast.

 

[Ratchetbirds]

I had all kinds of tube powered electronics as a kid. There used to be tube testing stands at the end of the check-out lanes in the grocery stores. I had a short wave radio over my bed and a really long single strand wire antenna. Spent many hours listening to sounds from around the world.

 

[rohmell]

How about a CDI built from tubes?



Of course, you would need to carry along a battery to power the filaments of the tubes.

 

[rohmell]

I had all kinds of tube powered electronics as a kid. There used to be tube testing stands at the end of the check-out lanes in the grocery stores. I had a short wave radio over my bed and a really long single strand wire antenna. Spent many hours listening to sounds from around the world.

I have one of those tube testers that could usually be found in larger drugstores, grocery stores, and in Radio Shack back in the olde days.

To the left you can see a big ole Tektronix tube scope, model 545A, and below the tube tester is another 545A, and yes, they are fully operational and calibrated.

 

[Ratchetbirds]

Now that brings back memories. I could build a backpack power supply for the tube cdi <G>. We had a huge radio/record player my old man bought at a garage sale that would record 78's as well as play them but the neatest part was a tuning tube we called a magic eye? The top of the tube would illuminate and the more that illuminated the better the signal. I've seen it in many other old radios. I don't have any radios at this time but I do have a pair of WWII/Korean war vintage feild phones with the hand crank magnetos in them. That is why I bought them.

 

[rohmell]

I remember using some old test equipment that had a 'Magic Eye' in it.
I think some of the Heathkit test equipment kits used them.

 

[dakota47l1]

Also, bicycle tires use tubes inside of 'em.

But, for real, military aircraft, such as the the MIG-25 still use tubes:
The majority of the on-board avionics were based on vacuum-tube technology, not solid-state electronics. Although they represented aging technology, vacuum tubes were more tolerant of temperature extremes, thereby removing the need for providing complex environmental controls inside the avionics bays. In addition, the vacuum tubes were easy to replace in remote northern airfields where sophisticated transistor parts might not have been readily available. With the use of vacuum tubes, the MiG-25P's original Smerch-A (Tornado, NATO reporting name "Foxfire") radar had enormous power – about 600 kilowatts. As with most Soviet aircraft, the MiG-25 was designed to be as rugged as possible. The use of vacuum tubes also makes the aircraft's systems resistant to an electromagnetic pulse, for example after a nuclear blast.

i like you man but you are way to technical for me!!!i wont call you a dork i'm nicer than that!!LOLJ/k

 

[rohmell]

i like you man but you are way to technical for me!!!i wont call you a dork i'm nicer than that!!LOLJ/k

Actually, it's from Wikipedia:
Mikoyan-Gurevich MiG-25 - Wikipedia, the free encyclopedia