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RZ250 CDI Question

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  • RZ250 CDI Question

    Can someone tell me if the RZ250 CDI will work on the previous 81-82 model or on the aircooled model?

  • #2

    (below) An example of the technique to rig a bad CDI to work. When you tighten the clamp with the dowel on top it tweaks the circuit board in the CDI so it works again. This will make it work till you can afford to replace one.


    84 to 85 RZ350 CDI Conversion by Tom-S

    After hearing about the problems other people had with the 84 CDI, I thought I was just lucky, until my CDI started acting up. The bike would just quit without warning and couldn't be re-started for about 5 to 10 minutes. Once or twice a season was bad enough but then it got worse. I knew I had to do something. I found the article on CDI exchange by Martin Kieltsch and deceided to try something. I got a Brazilian CDI from Viking, thinking it would work the same as the 1UA-50. Unfortunately, no matter how I hooked it up the bike would not rev (rev???) over about 4700 RPM!!! Back to the drawing board. Thought I would have to get a whole package: CDI, stator, and rotor. Kept an eye on E-Bay and the RZ sites for parts. About 2 weeks ago on Alek's site I came across a post by IanG1 who said he successfully installed an 85 CDI on an 84 RZ. I contacted him for more info, scored a CDI on E-Bay, installed it , and became a happy camper!!

    This is how you do it. (I cut the wires from the old CDI and installed bullet connectors) All wires from the 84 harness go to the corresponding colored wires on the 52Y-50 CDI except: the red wire from the harness goes to the green wire of the CDI, both the green and black/white wires from the harness go to the red/white wire of the CDI. Tested in a short (20 mi.) ride between rain storms, revs to over 10K, no problems!!

    That's what it would seem like but since resistance values R to Br and Br to Gr are similar for both 84 and 85 it can't be. Esentially, I know it work's, but can't explain why!! The kill switch wire is connected to the R/W wire of the CDI since the 85 CDI does not have a provision for a kill switch like the other models.


    This is my attempt at a translation of "Martin Kieltsch rd bible. For experimental use only. I am not responsible if this information is incorrect because of my error or any one elses. I did the best I could. This has to be good enough. RZ350 LAND

    The YPVS series have three different stators, rotors and CDI units

    83-84 RZ350

    The CDI of the first two years of construction (' 83 and ' 84) carries the marking 29 K-50. The 29K-50 CDI has a square four-fold plug, a t-shaped connector for the load coil (brown, green and red) , a two-fold plug for the Pick UP and a black ground wire. One can recognize the stator (marking اY) by the appearance of the load coils. This stator has a thicker coil in the center and on the right of and on the left of two smaller, which are curved like horns. The stator is marked اY and/or 2CY. It has two drillings and two long holes. The rotor has the marking 29L - 50

    85 RZ350The 1985 31K has changed Stator and CDI. The CDI is marked 52 Y-50. The 52 Y-50 CDI has also only 8 connections (the other two to have 9). This CDI is missing the black-and-white cable, which serves to turn the engine off by the kill switch. The 85 stator is marked بZ or 8DX. The stator has two somewhat thicker load coils. Safe distinguisher of the 85 stator is the red-white cable at the load coil, which is always red with both other stators! A further indication is the missing connector for the "load coil", which into three individual plugs (brown, green and red-white) is divided. The Rotor has the marking 51L - 50 .86-95 RZ/RD350

    The 86-95 CDI are marked 1UA - 50. The Stator looks outwardly like the ' 85 stator,but it has different plugs. A square four-fold plug, a flat connector for the load coil (brown, green and red) , a flat two-fold plug for the Pick UP and a black ground wire. The marking on the stator is 1FX. The rotor may posess the markings 1UA, -50,VCD 88,(1FY).

    Combinations:The 86+ Stator functions only with the suitable rotor(VCD 88);The 86+ 1UA - 50 CDI will work without changes with a 85 31K bike. . The black white cable can remain free.

    One can also use the 1UA-50 CDI with the 83/'84 31K stator(اY/2CY). In addition one must change the plugs going by that the cables "red" and "green" of the load coil must be exchanged . If one connects same colors, she does not function!

    One can use the 85 (52Y- 50) CDI with the 84 or 86+ models. To connect an 85 cdi to an 86+ one connects the same colors and also put the black-and-white cable of the wiring harness to the black-yellow cable of the CDI. A second possibility is, black-and-white cables to the red cable to the CDI to also put (it functions both).To use an 85(52Y- 50) CDI on an 83-84 31K system you must exchange the colors red and green and put additionally the black-and-white cable of the wiring harness also to the black-yellow cable of the CDI. A second possibility is again to also put the black-and-white cable to the red cable to the CDI.

    If the black-and-white cable remains free, one cannot turn the engine off

    Chart Cipher:

    The 84 29K- 50 CDI will work with an 84 stator and an 85 rotor.

    The 85 52Y- 50 CDI will work with with the 84 rotor and 84 stator if you exchange R/Gr , S/W at S/G

    The 85 52Y- 50 CDI will work with 85 rotor with 84 stator if you exchangeR/Gr , S/W at S/G

    The 85 52Y- 50 CDI will work with 84 rotor with an 85 stator.

    The 85 52Y- 50 CDI will work with an 86+ rotor with an 86+ Stator if you S/W at S/G

    The 86+ 1UA- 50 CDI will work with an 84 rotor and an 84 stator if youexchange R/Gr .

    The 86+ 1UA- 50 CDI will work with an with an 85 rotor with an 84 stator if you exchange R/Gr

    The 86+ 1UA- 50 CDI will work with an 84 rotor with an 85 stator

    The 86+ 1UA- 50 CDI will work with an 85 rotor and an 85 stator

    The only thing I can't figure is what "S/W at S/G" stands for. Stripe?.....hmmmm

    UPDATE: Thanks to some guy on RD forum "

    s/w = black/white
    s/g = black/yellow

    There is at least 3 CDI types on YPVS 350 Models:

    29K-50 for 31K 83-84
    52Y-50 for 57V/1JF 85-86
    1UA-50 for 1WT / 1UA / 3DH1
    ???? for 4CE6 (RD350R).

    CDI Testing Procedure
    I wrote this a few years ago to try and help someone here on the forum nail down a problem they were having. It is based off of reading from my own RZ.

    CDI Troubleshooting
    CDI theory:
    The CDI ignition takes a pulsed current generated by the low or high-speed charge coil (depending on engine RPM) and charges a capacitor. This stored charge is then discharged into the primary winding of the ignition coil causing the plugs to spark (both at once). The timing of this discharge to the coil is triggered by the arrival of a small electrical pulse generated by the pickup coil and electronically delayed to occur at the proper time by circuits internal to the CDI module. The ignition, engine run and side stand control unit provide a circuit to ground to "kill" the ignition. There is an old saying "garbage in equals garbage out" If any of these signals are missing or a short circuit to ground occurs in the "kill" circuit, the CDI will be unable to function properly.

    Engine mechanical:
    Suspected ignition problems are sometimes not that at all but other engine mechanical failures so before we test electricals lets first check the following basic items:
    1. Engine has good compression and the difference between cylinders is small. Upper 90's for PSI is good for a cold engine (5 kicks with throttle wide open).
    2. Carbs are mechanically balanced.
    3. Check auto lube pump adjustment
    4. Install a set of NEW plugs. The secondary winding of the ignition coil is attached to both plugs. In order to complete the circuit the current must flow down one plug wire to the plug, jump the gap, go thru the engine cylinder head to the other plug, jump that gap then go back up the wire to the coil. If you interrupt this circuit, neither plug will fire. If you do experience one plug sparking without the other, the circuit is being completed another way, perhaps through the plug wire insulation to the frame or perhaps internal to the ignition coil to the metal core which is bolted to the frame.

    Engine electrical:
    The RZ electrical connectors can corrode pretty bad. The engine vibration helps to maintain good contact but a bike that has set for a while can develop electrical "ghosts" quite easily. So lets start by separating, inspecting and re connecting all the electrical connections associated with the ignition system. When that is completed take the following readings. The following readings can be taken using the standard test leads that come with most digital volt ohmmeters. The RZ electrical system is connected together with molded nylon "molex" or "spaid" connectors. All the initial readings are taken with the circuit under their normal electrical load. This means that all the connectors are connected and you take the reading by sliding the test probe tip into the molded connector alongside the proper colored wire until it makes contact with the metal portion of the electrical connector. You need a digital voltmeter as the delay in the needle reaction of an analog meter might miss some of these very small signals
    1. On the CDI bundle find the connector with the black wire with a white stripe running along it. Put the red test lead in along side this wire. Hold the black lead against the bare metal of a head bolt. Set the meter to read resistance. With the kickstand up, engine in neutral, the kill switch set to run and the ignition key to on you should see greater than 30K OHMS of resistance. If you turn off the key or kill switch the resistance should decrease to near 0.

    ALL OF THE FOLLOWING READINGS ARE TAKEN DURING 5 RAPID KICKS! The object is to keep the engine rotating long enough for the digital meter to sample the signal and display a reading. This is easiest with the spark plugs removed, the plug wires connected to the plugs and the plug body connected to ground on the engine case to complete the circuit. What also works well is to tape the metal bodies of 2 spark plugs together, with the insulators pointing away from each other. Attach the spark plug wires to these and this will also complete the coil secondary circuit.

    2. On the end of the CDI wiring harness you will find a 3-wire connector that has a brown, red and green wire. Slide your black probe in beside the brown wire and the red probe in beside the green wire. This is your low speed winding. Set the meter to read AC volts, turn on the ignition and kick the machine over 5 times quickly. You should see, while kicking, a reading of 25 Volts AC.
    3. Now move the red test lead to the red wire (measuring brown to red) this is the high speed winding kick over the machine with the ignition on and you should see 4.5 Volts AC.
    4. On the CDI bundle there is a 2-wire connector with a white with red stripe wire and a white with green stripe wire. This is your pickup coil connector. Slide your test leads in beside these 2 wires. When you kick the starter rapidly you should see 0.3 Volts AC
    5. On the CDI bundle there is a 2-wire connector with an orange wire and a black wire. Slide the meter probes in beside these wires. This is the CDI output to the ignition coil primary winding.
    When the starter is kicked rapidly, you should see 0.4 Volts AC.
    If any of these voltages are missing one of 2 things is happening. Either the source device is not generating the signal or the destination device is shorted and the signal is being loaded down. If one of the signals is missing, separate the electrical connector for that signal (electrically unload it) and connect your meter to the source side and repeat the test. Here are the unloaded readings for the above listed signals
    2. Low speed charge coil 50 Volts AC unloaded
    3. High speed charge coil 4.5 Volts AC unloaded
    4. Pickup coil 0.3 Volts AC unloaded
    5. CDI output 24 Volts AC unloaded
    In the case of signals 2,3 and 4 if the loaded test is bad and the unloaded test is good do a resistance test of the source device. The low speed coil (test 2) should read 225 ohms (or 133 ohms depending on engine type). The high-speed coil (test 3) should read 5.3 ohms and the pickup coil (test 4) should read 115 ohms. If the resistance check is good the CDI is most likely at fault.
    In case the signal 5 load test is bad and the unloaded test is good, measure the resistance of the ignition coil primary winding. The primary winding resistance is around 0.33 ohms. If it is OK then the CDI is most likely at fault.
    If all the above readings are good then check the secondary winding of the ignition coil, the measurement from one plug cap to the other should be about 23K ohms. The plug caps themselves "screw" (twist counterclockwise) off of the plug wires each plug cap should read about 10K ohm when measured by itself. The coil and plug wires alone should read 3.5K ohms. It is possible for the coil secondary to be breaking down under high voltage but measure just fine with the ohmmeter. If you are getting the proper signal on the black and orange wire to the coil with no spark out into NEW plugs, then the coil is probably at fault. I had this happen intermittently for about a year, I finally found it by connecting up a meter to the black and orange wires and taping it to the tank where I could see it. The next time the bike quit, while I was coasting in gear the input voltage was still there with no spark out, Good in, garbage out. told me it was the coil. One final word of caution. DO NOT ATTEMPT TO MEASURE THE OUTPUT SPARK VOLTAGE FROM THE IGNITION COIL! IT WILL DESTROY THE METER!
    Originally posted by Bendito
    If we get to a stop and we are missing a dozen bikes and you are last, it was your fault. Don't be that guy. No one likes that guy.


    • #3
      Thanks for all you efforts in reply but nothing there helps answer the question.Thought someone may have tried this before.


      • #4
        Thanks gozer - that info will be very useful to my son who still has a power valve issue after the servo motor fused - the CDI may have suffered as well.

        On the original question - I doubt it. The old air cooled bikes are very different and I don't think the LC was a power valve set up. They are all different development stages and the RZ CDI is designed to run power valves.


        • #5
          i think its just a matter of wiring it up leave the PV wires dangling. the ignition curve will be different but how different could they be? i think it would work just not be optimized for the different port timing. water cooled timing might be too aggressive for air cooled but you can retard by moving the trigger coils.

          if you cannot get the correct CDI get a zeeltronic which is programmable.
          Originally posted by Bendito
          If we get to a stop and we are missing a dozen bikes and you are last, it was your fault. Don't be that guy. No one likes that guy.


          • #6
            Try it, they are only 70 bucks from a wreckers, or you could buy the one on gummers for $125, comes with jousting sticks


            • #7
              Originally posted by scanigan View Post
              Can someone tell me if the RZ250 CDI will work on the previous 81-82 model or on the aircooled model?
              so what bike do you have
              an rz or an rd?
              and what year?


              • #8
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                Is it one of these?


                • #9
                  why not just get a Zeeltronic replacement?
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