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Cdi unit

Discussion in 'XJ Technical Chat' started by Johnboii, Jan 11, 2019.

  1. Johnboii

    Johnboii New Member

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    Hi. New to This site.
    But hoping someone can help me.
    I bought a xj600 divertion to convert it into a quad.
    It's bein running great for last year since I finished the build but a month ago I went to start and no spark to 2 and 3.

    Anyways the culprits ended up being the cdi.
    So I went online and got one off eBay.

    Put it on today and now I'm getting no spark on any coils.

    I'm wondering if anything changed over the years with the cdi unit or if there's another earth bein added or live to the cdi.
    If I plug the old one In I'm back to spark on 1 and 4.

    The cdi both look the same and same amount of pins etc...

    Not sure on year of the xj I bought as it was a none runner with just the frame and engine..

    The cdi I got online was of an X reg.

    Thanks in advance
     
  2. bensalf

    bensalf Active Member

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    it could be a faulty one you bought or it could be the wrong one for the engine.
    but it would be a T.C.I. (transistor controlled ignition) not cdi (capacitor discharge ignition) when searching on ebay put in tci, or you will get all kinds of ignition devises.
    so x reg would be 2001 ish, what year is the engine and how do the codes on the t.c.i's compare. what is the engine number, you can determine the year from the number
    is the model designation 4BR
    stu
     
  3. Johnboii

    Johnboii New Member

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    Hiya mate.
    After looking on the internet I think I've got the wrong one. I need an older TCI even tho it has the same plug I see the newer xjs (2001) have 12 wires going to TCI where as mine only has 8.
    The code on one I bought us 4br but typically the old ones number has gone off it so I cannot compare.
    As for the engine number do you know where I could


    Yeah the engine says 4br 040911x and the new cdi says 4br xe on it
     
  4. jayrodoh

    jayrodoh YimYam Premium Member

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    Did you ohm out the coils and the pickup coils? The fact you don’t have spark on 1 coil could be something other than the TCI. Cheaper than replacing TCI unit.
     
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  5. XJ550H

    XJ550H Well-Known Member Premium Member

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    have you tried swaping your ignition coils so that 2&3 become 1&4 to eliminate the coils and plug caps as the problem?
     
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  6. k-moe

    k-moe Pie, Bacon, Burbon. Moderator Premium Member

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    +1
    The TCI controls spartk timing, duration, and advance. An aircooled XJ engine will typically adle with the wrong TCI, and fire on both coils.
    This very much sounds like the TCI might not be at fault.
     
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  7. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Later TCI's (depends on model and year when the change occurred) use a DIGITAL TCI (and, it will say DIGITAL on the TCI's foil label, or, on some models, cast into the plastic case), and those models require the use of a DIGITAL TCI unit and cannot use the earlier version TCI units (and, the earlier models with a standard TCI cannot use the later version TCI, either). Pull off the left side crankshaft cover and look at the p/u coil(s).............if there's only 1 p/u coil, that engine is designed for a DIGITAL TCI. Two p/u coils means it use a standard (not-quite-analog, but definitely not digital) TCI.

    The 4BR- TCI units came in 2 flavors, 4BR-82350-00-00 (1992-96, depending on country, ink-stamped 4BR-00) and 4BR-82350-10-00, which are for 1994-2002 (again, depending on country and model bike, and the case is ink-stamped as 4BR-10). I believe both of these are DIGITAL TCI units (although it doesn't say so on the case, and these TCI units have no foil ID labels).

    The best chance you have of finding the correct TCI is to first identify the engine properly, using the link to the guide posted earlier.
     
    Last edited: Jan 11, 2019
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  8. Johnboii

    Johnboii New Member

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    Well yeah that would match up with what your saying yeah. I have a 1996 engine and the TCI I bought is for a 2001 model. The company I bought it off is going to c if they have the earlier model TCI. Cheers for your help
     
  9. Johnboii

    Johnboii New Member

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    Yeah I tried and I checked the resistance on the plugs and caps and worked my way back.


     
  10. Johnboii

    Johnboii New Member

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    You can see the diode inside that controls 2 and 3 is burnt out IMG_20190112_104048.jpg
     
  11. jayrodoh

    jayrodoh YimYam Premium Member

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    Okay cool, yeah you definitely need to replace that. We’ve seen a lot of threads where people jump to the TCI conclusion where it wasn’t.

    Got any pics of the quad?
     
  12. Johnboii

    Johnboii New Member

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  13. k-moe

    k-moe Pie, Bacon, Burbon. Moderator Premium Member

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    That burned diode is really a burnt transistor.
    An equivalent should still be available from an electronics supplier. They aren't too difficult to change, just be sure to get thermal paste to set under it so the heatsink can work at its best.

    It would also be worthwhile to replace the electrolytic capacitors, particularly if you see any that are swolen or that have signs of leakage.

    How are your soldering skills?
     
  14. Johnboii

    Johnboii New Member

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    Oh ok. N yeah now I've took the box completely apart I can see it shouldn't be too hard to change if I can get a tiny needle size bit for my soldering gun

    Do you know if it has to be the same code on the transistor as the one I'll buy. Just im finding it hard to find one online with same code? Cheers for your help
     
  15. k-moe

    k-moe Pie, Bacon, Burbon. Moderator Premium Member

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    1. Don't use a soldering gun. All you need is a small 10 or 15 watt soldering iron that is intended for PCB repair. Using anything hotter will damage the new transistor.
    2. That transistor has been superceded by a new one (at least once), so you will need to use a cross-refrence guide in order to find an equivalent.
    components.html

    This thread will give you a good overview of the repair process, and I think the replacememnt transistor listed in the thread is still available.
    tci-rebuild-thread.38234
    Be sure to read the threads that Darkfibre links to in that thread, as his repair was a bit more extensive than what you need to do, and he skipped over showing the process of desoldering and resoldering.

    EDIT: The links in Darkfibre's thread are from the old site, so are broken. This is the thread that has the transistor info you'll need. circuit-board-level-help-required.37190
     
    Last edited: Jan 12, 2019
  16. Johnboii

    Johnboii New Member

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    Ok mate. Thanks muchly. Ill . I'll see how I get on.
     

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