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gs450 charging+rpm probs?

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    gs450 charging+rpm probs?

    Hi all, have a curious problem and looking for some feedback.
    It appears I have a problem w/my charging system which is under charging my battery. I am only getting about 13.7v at 5000rpm. I did a no load stator check and am only getting about 65v at 5000rpm. New and charged battery as well as tight clean connectors.
    My question is this: when the charging problem first became apparent, the rpms climbed to about 3000 and wouldn't drop. Idle speed screw made no difference. Could charging prob have any connection to idle speed or am I looking at 2 unrelated problems that happened to occur at the same time?
    Thanks in advance for any ideas.

    #2
    I may be wrong as I'm still learning this stuff, but I'm pretty sure that sounds like two separate problems to me. High idle like that is usually intake related from excess air getting in through dodgy inlet boots or an unsealed airbox etc.

    Definitely looks like you have a stator issue too given the 65 volt reading.

    From the Clymer:

    The AC voltmeter should indicate 75 volts AC or more (65 volts for GS425 models) for each test connection. Less than 75 volts AC (65 volts for GS425 models) on any test connection indicates a faulty alternator.

    Probably best for someone more knowledgeable to chip in, but that's where I'd be starting...
    1982 GS450E - The Wee Beastie
    1984 GSX750S Katana 7/11 - Kit Kat - BOTM May 2020

    sigpic

    450 Refresh thread: https://www.thegsresources.com/_foru...-GS450-Refresh

    Katana 7/11 thread: http://www.thegsresources.com/_forum...84-Katana-7-11

    Comment


      #3
      Originally posted by MAdams450 View Post
      Hi all, have a curious problem and looking for some feedback.
      It appears I have a problem w/my charging system which is under charging my battery. I am only getting about 13.7v at 5000rpm. I did a no load stator check and am only getting about 65v at 5000rpm. New and charged battery as well as tight clean connectors.
      My question is this: when the charging problem first became apparent, the rpms climbed to about 3000 and wouldn't drop. Idle speed screw made no difference. Could charging prob have any connection to idle speed or am I looking at 2 unrelated problems that happened to occur at the same time?
      Thanks in advance for any ideas.
      As pete said, these two problems are most likely unrelated. What's wrong with 13.7 v- not great but stlll should charge battery. Review the gs charging system health stuff. Your R/R might be failing, but the connections from R/R to battery have to be real good.
      1981 gs650L

      "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

      Comment


        #4
        Originally posted by tom203 View Post
        As pete said, these two problems are most likely unrelated. What's wrong with 13.7 v- not great but stlll should charge battery. Review the gs charging system health stuff. Your R/R might be failing, but the connections from R/R to battery have to be real good.
        I would at least want to see 14.0V. If he can't get there it could be a failing stator or bad connections.

        Comment


          #5
          Thanks for the input guys. I think I figured it out. The choke lever somehow came disengaged from the shaft that actuates the choke assy.(the choke was left partially engaged) I feel stupid now. Anyway, I tried a different voltlmeter and checked again after charging the battery. I am now reading 74v on the stator, but the regulator output is weird (climbs to 13.8v at about 3500rpm, but then begins dropping to about 12.7v as the rpms increase to 5000rpm) looks like bad regulator to me. Thanks again for the feedback.

          Comment


            #6
            Originally posted by MAdams450 View Post
            Thanks for the input guys. I think I figured it out. The choke lever somehow came disengaged from the shaft that actuates the choke assy.(the choke was left partially engaged) I feel stupid now. Anyway, I tried a different voltlmeter and checked again after charging the battery. I am now reading 74v on the stator, but the regulator output is weird (climbs to 13.8v at about 3500rpm, but then begins dropping to about 12.7v as the rpms increase to 5000rpm) looks like bad regulator to me. Thanks again for the feedback.
            The probability a new R/R will do the exact same thing is likely over 90%, in other words you don't have a R/R problem. It is the wiring and there are 3 to 4 other guys posting near the exact same symptoms right now.

            I posed in each of those other threads links to "voltage fold back". U have to measure the voltage drops at 5k RPM to confiorm that is the problem.

            Comment


              #7
              Originally posted by MAdams450 View Post
              Thanks for the input guys. I think I figured it out. The choke lever somehow came disengaged from the shaft that actuates the choke assy.(the choke was left partially engaged) I feel stupid now. Anyway, I tried a different voltlmeter and checked again after charging the battery. I am now reading 74v on the stator, but the regulator output is weird (climbs to 13.8v at about 3500rpm, but then begins dropping to about 12.7v as the rpms increase to 5000rpm) looks like bad regulator to me. Thanks again for the feedback.
              Make sure you have a really good ground from R/R to battery negative- direct is best. As rpms rise and stator output increases, you need decent connections to avoid voltage dropoff.
              1981 gs650L

              "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

              Comment


                #8
                Originally posted by tom203 View Post
                Make sure you have a really good ground from R/R to battery negative- direct is best. As rpms rise and stator output increases, you need decent connections to avoid voltage dropoff.
                The connections normally associated with a mysterious fold back are at the "T" between the battery and R/R (+) and the fuse box.

                Comment


                  #9
                  Originally posted by posplayr View Post
                  The connections normally associated with a mysterious fold back are at the "T" between the battery and R/R (+) and the fuse box.
                  Sure, but the current has to travel the complete circuit, and the grounding side is an easy target for corrosion and resistance.
                  1981 gs650L

                  "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

                  Comment


                    #10
                    Originally posted by tom203 View Post
                    Sure, but the current has to travel the complete circuit, and the grounding side is an easy target for corrosion and resistance.
                    I hope most people do their grounds; it is the "T" and fuse box that are the last to get attention

                    Comment


                      #11
                      All the connections are very clean & tight. I measured no voltage drop across any wires or connectors at 5000rpm. The bike has no fuse box, only a single fuse holder that has already been replaced w/a spade type fuse. I removed the r/r and noticed a crack in the epoxy on the back side. I'm assuming the r/r burned up due to bad connections that have since been repaired.

                      Comment


                        #12
                        Originally posted by MAdams450 View Post
                        All the connections are very clean & tight. I measured no voltage drop across any wires or connectors at 5000rpm. The bike has no fuse box, only a single fuse holder that has already been replaced w/a spade type fuse. I removed the r/r and noticed a crack in the epoxy on the back side. I'm assuming the r/r burned up due to bad connections that have since been repaired.
                        Ok. if you're confident about your connections, try a different R/R- that crack doesn't inspire confidence.Member duaneage has best deals on quality units that will inspire confidence.
                        1981 gs650L

                        "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

                        Comment

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