Help interpreting test results? Bad mag AND CDI?

Discussion in '2 Stroke Bicycle Engines & Kits' started by squonk, May 7, 2011.

  1. squonk

    squonk New Member

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    Hi, all. I am so glad I found this forum. Spent about five hours reading here last night after completing my build and making myself look like a fool in front of the neighbors when it wouldn't start.

    It's a 2 cycle Chinese kit from bikemotorkits.com. The sticker on the magneto cover identifies the mfr. as Rico group. The problem is the apparently all-too-common "no spark" one. Fuel is reaching the plug. Clutch seems to be working as it should. But electrically, it's dead. So I printed out some of the recommended CDI and magneto test procedures and headed out to the garage this morning. I'm including my results here in the hope that someone can help me interpret them. My read is that both the CDI and magneto are defective. But since the odds of that should be relatively low, maybe someone can point out a mistake I've made or offer a suggestion.

    Here are the tests I ran. My results are in parentheses following the expected values posted in the forums:

    CDI:
    Black to Blue 1150 Kohm to 7.6 Mohm (No reading)
    Black to plug 2.6 Kohm to 2.17 Kohm (2.4 Kohm)
    Blue to plug 1150 Kohm to OPEN (No reading)

    Magneto (all solder points under the cover seem good):
    Blue to White 327 - 349 ohm (No reading)
    Black to Blue 327 - 347 ohm (No reading)
    Black to White 2.1 ohm (3.1 ohm)
    Black to GND 0 - 0.3 ohm (1.4 ohm)
    Blue to GND 327 - 347 ohm (No reading)
    White to GND 2.1 - 2.3 ohm (3.4 ohm)

    Thanks in advance for any help. I've also sent the results to the vendor, but I'm thinking I might get a quicker response here...
     
  2. Mac

    Mac New Member

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    I got these specs from 2door(experienced mechanic)

    Mac,
    I hope this helps. If not, ler me know.
    Tom


    Use Low Ohm-Meter Scale About 200 Ohms

    1) Check Ohms between BLACK wire and WHITE wire. Reading should be around 2 Ohms
    2) Check ohms between BLUE wire and WHITE wire. Should be around 300-400 ohms.

    CDI

    Use Ohm Meter High Scale About 200-K
    1) Positive lead on BLUE wire and Negative lead on BLACK wire should read infinite (no activity)
    2) Positive lead on BLACK wire and Negative lead on BLUE wire. Should be about 130-150 K-ohms
    3) Positive lead on Spark Plug wire and negative lead on BLUE wire. Should read between 135-155 K-ohms

    Switch to Low Scale 20K
    4) Measure between Spark Plug wire and Black lead. Should be about 2.5 - 2.7 K- ohms

    Hope this helps, don't forget to disconnect the kill switch and make sure you read the spark plug wire when it's NOT CONNECTED to the spark plug,

    Mac
    Mac
     
  3. squonk

    squonk New Member

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    Thanks for your reply. These tests look similar to the ones I did with the exception of the polarity on the CDI tests. So I did them again and put my results in parentheses.

    (I got 19 ohms)
    (I got no reading)

    (I got no reading)
    (I got no reading)
    (I got no reading)
    (I got 2.4 ohms)
    The kill switch is completely disconnected. Thanks again. I didn't get any new info., but now what I have may be more complete.
     
  4. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Check it for spark with the kill button completely disconected.
    If that doesn't work?, it's almost always the mag-coil that goes bad.
     
  5. squonk

    squonk New Member

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    Yep, the kill switch is completely disconnected. I suspect the magneto, but since I'm also getting no readings on the blue wire of the CDI that's why I'm thinking I got a double whammy of bad parts.
     
  6. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Replace the magneto first. That's most likely the problem.
     
  7. rohmell

    rohmell Active Member

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    Looks like you get no reading when checking between the blue wire and anywhere else on the magneto. The blue wire seems not to be connected to anything somehow, and you need that blue wire for the ignition system to work, so replace that magneto unit first.

    The CDI has semiconductor components inside and depending on your meter, you might not have enough Vf (forward voltage) to 'activate' the semiconductor junction for you to get a reading.

    I thought Rico group was BGF?
     
  8. squonk

    squonk New Member

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    Didn't read enough last night to know what BGF is, but I agree about the magneto. I took it out and re-did all of the solders, but still no joy. I'm hoping the vendor will replace the magneto for me as it was DOA.
     
  9. rohmell

    rohmell Active Member

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    BGF stands for BoyGoFast, who is a vendor of motorized bicycle kits on eBay.
     
  10. squonk

    squonk New Member

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    :) I like that. If I ever get the bike running, I may screen print that on a t-shirt to wear while riding.

    This kit didn't came from a vendor in Michigan, but I do think they have an ebay presence, too. Maybe it's all one and the same.
     
  11. Mike B

    Mike B New Member

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    The high voltage winding on your magneto is bad (open circuit)
     
  12. squonk

    squonk New Member

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    Hi, Mike. Thanks for the reply. That's the conclusion I reached, as well, but it's good to have the confirmation. I wrote the vendor to ask for a replacement, so we'll see how it goes.
     
  13. gubba

    gubba New Member

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    squonk.......

    my bus card says "installation and repair" and i have built over 30 china girls.
    not one single build has the white wire hookedup to anything! I have yet to have any coil or mag go bad.
    i make a good portion of my money replacing mags from having the white wire joined into the electrical system.
    wire black to blac/blue to blue from the mag to coil. put either kill switch wire into the black set and the other one to the blue set.
    you have likely spiked the mag and or the coil.
    i know i will get a lot of flack from this but i have yet to have to replace a mag with any of my builds to date.


    stay dry
    gubba
     
  14. rohmell

    rohmell Active Member

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    No flack from me. I don't know where people are getting the idea to use the white wire.

    The CDI wire colors are black and blue, the magneto wires are black and blue (ignoring white), how hard can it be to figure out this wiring?
     
  15. Eric2.0

    Eric2.0 New Member

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    I got a nice multi meter today, but I have a stupid question.

    How do you use it? When measuring the wires say the blue and black, you put a lead on each wire then read it?
     
  16. rohmell

    rohmell Active Member

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    yes, when on an Ohms scale, you put the leads on and read the display. For semiconductor devices(such as those that are inside the CDI) you have to read the display, reverse the leads and read the display again due to polarity, but this also depends upon if the meter has enough voltage available at the leads to turn on the semiconductor device.
    Here's a quick tutorial:
    Shavano Music Online - Using a Volt Ohm Meter
     
  17. squonk

    squonk New Member

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    Re: Help interpreting test results? Bad mag AND CDI? - SOLVED

    Hi, guys. Thanks for your input. It was, indeed, the magneto. After a few attempts, I managed to reach the vendor and they sent a replacement.

    And, gubba, I don't have the white wire connected to anything. I read many posts here advising against that and you confirm what they were saying.

    I appreciate all the advice, guys.
     
  18. wyatt808

    wyatt808 New Member

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    Hi i have the same problem. My friends parents own a auto shop. they suggested the grounding too. A good idea with the grounding is you can also add a small toggle switch and hide it on the bike so that if anyone steals it they cant use it. But i had the same problem i took it to their shop and they did tests and i have no power coming out of my magneto or CDI too. I asked an electrician and he too said they are both bad. I contacted the supplier "gasbike" because all my spark plug, spark plug cap, gas tank, CDI and magneto were all broken or damaged. They said they only replace the engine under warranty. But in conclusion you probably need to replace the magneto see if that works then replace the CDI.
     
  19. flmotorbikes

    flmotorbikes New Member

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    I would call up the vendor for the operating instructions (OI)
     

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