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GS550 Stator &/or R/R bad; Stator Papers Test Results Interpretation

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    GS550 Stator &/or R/R bad; Stator Papers Test Results Interpretation

    Hi all,

    I'm fairly new here but not completely new to working on bikes or electrical work. Believe it or not... I have some electrical problems on my newly purchased '78 GS 550.

    I've gone through quite a bit of the stator papers testing and wanted to share with you where I'm at currently.

    I'll start with the symptoms. When I bought the bike the headlight was burned out, I replaced the bulb with another cheap Sylvania H6024 7" sealed beam bulb. This replacement lasted less than a day before burning out again. Also, while the headlight was working, I remember noticing that the brightness of the bulb was largely influenced by the RPM. When the bike rev'd up the headlight got substantially brighter.

    The first thing I did today was measure the battery: I did this first without having started or even turning on the ignition switch in about a week, and then again after turning on just the ignition. Both of the numbers I got from the multimeter indicated a good/full charged normal battery as according to Stator Papers page 3 (http://www.thegsresources.com/statorpapers3.php). I believe the numbers were about 12.89V before ignition and then 12.35V after turning on the ignition. Because my headlamp is burned out, should I be concerned that my battery didn't actually pass this test? I'm concerned that having only powered the ignition coil (and not the headlight as well) the battery got a much smaller load then the author of Stator Paper 3 intended.

    Moving On: Next I ran through most of, if not all of the tests on Stator Papers Step 4. My R/R (regulator/rectifier) seems to have miserably failed the -Phase A Step 1 test. This is the test where you read the voltage between both battery terminals at 2500 & 5K RPM. At 5K I was definitely reading 17V or higher, and I believe I was reading about 17V or close to it, even when only rev'ing to only 2.5K RPM. This shouldn't get higher than 14.8V according to the Stator Papers. met
    -Phase A Step 2 Test: I read about .65 to .70 V. I did a simple check of continuity between R/R Red lead & the positive battery terminal using the audio 'beep'/diode test on my meter. This indicated a good connection, however, I'm not sure this is thorough enough a test. My simple test will indicate that there is an electrical connection at some level, but I'm not sure it will tell me whether or not the connection is good enough to cary the large current necessary for the R/R to actually function. In addition to this simple diode/beep continuity test I also pulled the fuse and cleaned some of the connections. I did not cut open the tape of the wire harness to check every bit of wire between the R/R & Battery.
    -Phase A Step 3 Test: My meter read .14V, which is less than the .25V amount the test required. The next suggestion by the stator papers suggests 'If you completed Steps 2 & 3 and still have less than 13.5 V at 5K RPM... etc.' Well, I have completed steps 2 & 3 somewhat but I'm not sure about a few things.
    Questions:

    1) Was my battery test thorough enough? If it wasn't and the battery isn't strong enough, would it likely make my other Phase A test results unreliable?
    2) Was my testing of the connection between Red R/R Lead & Positive battery terminal not thorough enough? This was suggested as a possible fault by having failed Phase A Step 2.
    3) If my battery is likely fine and my connection between Red R/R & Positive battery terminal is likely fine, what am I missing about Phase A testing? The Phase A Step 1 flow chart has a category/outcome for "Higher than 14.8v' which is the category my bike fell into. I then followed through Steps 2 & 3 and at the end of Step 3 I only see advice for bikes that fit into the 'Less than 13.5 V at 5K RPM' category. Where should I go from there?

    Moving On Again: Well I did what anyone else would and assumed I should continue to Phase B. My bike passed the first three tests of the Stator pretty well. I feel comfortable that the tests were done well and the results were within spec. The first 3 steps are 1 Stator windings resistance 0.5 to 2 Ohms, 2 no connectivity between stator leads & engine casing, 3 I measured > 60 V between any two stator leads. My stator seemed to fail the 4th test. I was reading about 30V between the Negative battery terminal and any of the three stator leads (at 5K RPM).

    Questions:
    4) Is this definitive proof that my stator is bad? Is it possible if the battery isn't up to par this result is tainted too?

    5) If my stator is bad, what exactly is wrong with it? I haven't continued through Paper 5 or 6 of the Stator papers so feel free to yell at me about asking questions without having done my homework. I thought that the stator was simply coils of wire, so I can see why tests 1-3 are relevant. I do not understand exactly what is being tested in test 4, or what is likely to have gone wrong in my case.

    Moving On Again On Again:
    As you might have imagined, I was pretty concerned about the state of my R/R because of my high 17V reading at 5K RPM in Phase A, so yes I did continue and test Phase C. Test 1 of Phase C showed no connectivity at all. There was no change when making the connection for any of the three yellow wires. This indicates an open circuit for all 3 yellow wires. I'm not sure exactly how my findings translate to the two possible results on the flow chart.

    Question:
    6) If I'm getting what appears to be zero connectivity in phase C test 1, what is this telling us? Which of the two options/categories should I follow on the flow chart? Does this put me into the '1.00 v or lower' or '1.5 v or higher' categories?

    Next; Phase C test 2 seemed to pass the test at about .61 - .62 V for all 3 yellow leads.

    Phase C test 3 returned absolutely no change on the meter, just as test 1 did. Again, what can I learn from this?

    Phase C test 4 seemed to pass just as test 2 did. Meter readings were at 615-625 mV (or .615-.625V)

    Wrapup: Are any of you familiar enough with my sort of situation to give me any answers here? I did go through all the motions as described in the stator papers, but some of what I did could have likely been done better. Also I don't fully understand parts of what I was testing which troubles me. As you can probably tell, I try to be a pretty thorough person and I know I didn't test the battery & connection between Red R/R lead directly to Battery as thoroughly as possible. Am I making a mistake in either of those that's large enough so discredit the rest of my test results?

    Anyways, I'm tired and going to bed. This write-up took longer than I expected. If I forgot to mention something or if you have any questions please ask, if I happen to thinking of any addt'l info I'll add it as a comment. Thanks in advance for any help at all. You guys have done a lot of the work for me already by putting together The Stator Papers and other information and I'm very grateful for all of it!

    Attached Files

    #2
    As soon as you are getting 17.0 volts you are overcharging and the R/R is suspect. Replace that and then start over.

    Without the headlamp it is less of a load test (5 amps less), so figure 1/2. So if you double the drop and still stay above 12.0 you are good.

    Comment


      #3
      I went with a Shindengen SH775AA which was listed on ebay as "SEADOO GTI GTR GTX RXP RXT .
      Part # 710001103"

      It is slightly used but I wouldn't have been able to tell by looking at it. I paid $72 shipped (the prices I found seemed higher than those mentioned in other threads here, USA shopper).

      I haven ran the bike much more than a few minutes since installing, but at 5K RPM I'm reading about 14.6 V across the battery terminals & my headlight didn't burn out when revving that high.

      Thank you posplayr for the help!

      Comment


        #4
        Good job, but did you follow thf other recommendations in gs charging health?

        Comment

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