Yamaha RD350LC YPVS CDI FIX problem?

Discussion in 'UK Motorcycles' started by glenb900, Sep 10, 2006.

  1. glenb900

    glenb900 Guest

    Yamaha (RD350 YPVS or also called the RZ350) CDI problem FIX?

    Yamaha RZ350's (especially 1983 and 1984 models) have a CDI problem
    causes it to fail over time. A used unit from a a newer model don't
    unless you replace most electrics. I heard of some people fixing this
    problem by taking the CDI apart and replacing or soldering the
    fault. It's hard to take the CDI apart but I never seen anyone release
    fix or a schematic of the CDI with test procedures.

    Does anyone have a schematic/circuit details or know how to test, FIX

    All the info I have listed here I found posted in newsgroups, etc but
    does not include repair info. If you change the stator/CDI/coils from a
    newer model, it will work BUT it would be nice to know how or why the
    units are failing and what (transistor/diode/resistor) needs to be

    PLEASE post any technical info about this problem.
    I'm interested mainly in the 1983/84 CDI info. New CDI's also have
    problems but
    don't have a high failure rate like the 1983/84 models. Someone below
    also said they fix the problem but never posted the fix and the e-mail
    1997 don't work anymore.


    This may sound obvious, but did you check the spark after it cut out.
    Supposedly there was a design flaw in the cdi box that caused them to
    fail at a high rate. My bike has a broken box. Have to preheat the box
    or park under the hot sun for it to start. If you have a bad cdi, it's
    $$$ to replace.


    My second CDI box quit this summer. BUT I fixed it !!!
    Took a couple of hours to dig through the epoxy and gravel but I
    have fixed it. I am about to attempt this on another box in a couple
    of weeks. Do not throw away your CDI boxes just yet. Just in case
    I have actually figured out how to fix them and it aint just a fluke.


    i assumed that the YPVS and
    ignition system would be nearly identical. I could not find any spec
    regarding the CDI unit, in fact the manual stated that Yamaha had not
    released details at the date of publication?


    tighten a large hose type clamp with a dowel on top mid-point applies
    to the circuit board in the CDI for it to work again. This is ONLY a
    temp fix
    so you can find a replacement or fix your old one.

    Three CDI types on Yamaha RZ350:

    29K-50 for 31K 1983-1984 RZ350
    52Y-50 for 57V/1JF 1985-1986 RZ350
    1UA-50 for 1WT/1UA/3DH1 1987 on ?
    glenb900, Sep 10, 2006
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  2. Try again, this time with a comprehensible posting.
    The Older Gentleman, Sep 10, 2006
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