is this the right info about cdi/magnet?

Discussion in 'General Questions' started by gone_fishin, May 20, 2007.

Tags: Add Tags
  1. gone_fishin

    gone_fishin Guest

    this tip is in the submissions forum:

    is this info applicable to the chinese components? if not, what are our specs?

    if you have the info, or any input, please post it here, & we'll edit it all together for the owner's manual.

    thanks 8)

  2. Guest

    Guest Guest

    I'd ask duane at thatsdax.
  3. gone_fishin

    gone_fishin Guest

    i'm asking the whole community, which he's part of, he'll jump in with some help too i'm sure.
  4. Guest

    Guest Guest

    I hope so, that is one place where my knowledge of I/C engines is horribly lacking. :???:
  5. gone_fishin

    gone_fishin Guest

    shoot, dude, i have nooo fargen idea at all, that's why i have to confirm before i can put it in the manual :???:
  6. jol

    jol Guest

    Theese were my readings, but this with a very weak spark (not starting), not sure which is the faulty part yet tho.

    1. 0
    2. 49.8kOhm
    3. 53.6kOhm
    4. 2.3kOhm

    1. 2.8Ohm
    2. 335Ohm
  7. gone_fishin

    gone_fishin Guest

    so, jol, it's a CDI problem?

    can anyone confrim the figures for us so i can archive them in the manual?
  8. lotsa_mpg

    lotsa_mpg Guest

    I don't know a thing about the specs, but being as we are on the topic of CDI's, I've a question concerning the recommended mouting position. The instructions call for mounting it on the front downtube and I can see that almost everyone has theirs mounted in such a position. However, when building a Dax engine mountain bike for my cousin, I could not conveniently mount it I ended up placing it on the underside of the top bar just under the tank. I could see no reason why it needed to be mounted in the recommended location. There's no moving parts in the box that I am aware of and having been around various small engines with CDI's for a couple decades, I've seen them mounted anywhere and I could see no real reason to have to mount it on the downtube. The mountain bike I built runs perfectly fine the way I have it positioned. However, maybe I am missing something? Perhaps with these Chinese engines, the CDI might fail prematurely if not mounted the way they want you to? I really can't see it, but you never know. Anybody have an opinion on this?

  9. gone_fishin

    gone_fishin Guest

    nope, never heard of CDI position affecting performance. i agree with you, i don't see how it would, excepting being too close to a heat-source.
  10. azbill

    azbill Active Member

    the only info I ever found said to keep as far from exhaust as possible (heat is electonics enemy)
    seeing as everything is electronic (not mechanical)and sealed in resin, I don't think position will have any effect
    they are usually on downtube for convenience
  11. JosephGarcia

    JosephGarcia Guest

    I had mine in the same position on my old mountain bike. Never affected anything. I was never told not to.
  12. dr_clabo

    dr_clabo Guest

    CDI COIL TEST (Use ohm-meter on high scale of around 200-K)

    Just take a reading from a new or proven coil that works and post the specs ! :razz:

    Hope this will help,
  13. gone_fishin

    gone_fishin Guest

    it all helps :)

    'cept for the part about we don't actually have those figures yet :p :p

    no biggy, that's why i posted this plea. i'm certainly not qualified to speak on ignition beyond the basic wiring. help will arrive sooner or later 8)
  14. dr_clabo

    dr_clabo Guest

    (you know this site has helped you very much already)

    I am at the office farting around on the computer instead of working right now.......

    BUT ! We need someone with a VOM (volt / ohm / meter) to go out and get a reading on a good coil / cdi unit.

    Hope this will help, guy,


    Otherwise, i will be home later and do it.....

  15. jol

    jol Guest

    Dunno, was sent a new magneto coil (same cdi) and i got one small fart/ignition of fuel, no visible diff in the spark strenght... Will call a friend and borrow his cdi tomorrow
  16. jol

    jol Guest

    measured up both my original and replacement magneto coil, and my and my friends cdi, same results.
    Now it's only the magnet itself, or maybe too much oil in the fuel... got it to ignite some going down a steep long hill atleast
  17. dr_clabo

    dr_clabo Guest

    Sorry so late.....

    On a brand new never used coil straight from the box, these are my readings:

    Black to Spark lead = 2.54K

    All other connection combinations were 0K - open.

    Just as a general rule, on an ignition coil, the primary coil does not communicate with the secondary coil.

    The CDI part is a "pointless" switch, so to say, that collapses the magnetic field by using a "pulse" as a switch trigger.

    Good luck,
  18. jfealy

    jfealy Guest


    I am having the same problem trying to find out why I can't get a spark. Could you tell me how you are taking your readings? Did you find a solution to your low or no spark. Thanks you jfealy