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1977 gs750 not charging

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    1977 gs750 not charging

    My 1977 gs750 is not charging the battery.. (it was, but not now, and the battery is good) I found browned insulation at thd bullet connectors between the stator and rectifier which tells me something went south. Each stator leg to another reads 1.5 ohms and all three are open to ground so it seems good. (I couldn't find specs for stator resistance does snyone know?) The rectifier reads .4 ohms ground to yellow and and .4 ohms yellow to red so I think that's good. I'm thinking the regulator (mounted under the battery box? Went south but idk how to test that. Googling and partzilla indicates my system does have the separate regulator snd it's a crappy design just shunting one leg of the stator somehow idk. Again googling seems to indicate the standard repair/upgrade is to use s Honda cb400 rectifier/regulator but I see the gs850 has s combination rectifier/regulator eould I be better to use that?
    1979 gs1000e (everyday) 1977 gs750 for sale
    1983 yam xj550 maxim streetbob sold
    1995 gsx750F everyday fighterjet 1990 gsx1100F for sale
    2000kaw zx600
    2003 BMW K1200GT sport tour
    2000Buel Cyclone M2 motorwork
    1984 Yam venture xvz1200 -long ride/cold ride ride gf ride..
    1978 Honda cb750F3 supersport top end (still)
    1976 Harley FL 3/8" S&S stroker - motor out way too long
    1980 Harley fxs80 - wacked good on this one

    #2
    There are literally thousands of posts here about fixing charging systems. Short answer: get a combo R/R SH775 and new stator. Wire like shown..,

    SH775 Install by nessism, on Flickr
    Ed

    To measure is to know.

    Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

    Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

    Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

    KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

    Comment


      #3
      Heed Nessism’s short answer. Measuring ohms is inconclusive, cuz when installed in running bike , the stator is tugged and tortured by the spinning magnet field.
      note that your bike probably has the older 12 pole stator , so make sure you get similar.
      1981 gs650L

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

      Comment


        #4
        You can do an AC test on the stator. Usually if that's the problem you'll see that one of the legs is dead. A lot of times you only need the new RR...
        1980 GS1000G - Sold
        1978 GS1000E - Finished!
        1980 GS550E - Fixed & given to a friend
        1983 GS750ES Special - Sold
        2009 KLR 650 - Sold - gone to TX!
        1982 GS1100G - Rebuilt and finished. - Sold
        2009 TE610 - Dual Sporting around dreaming of Dakar.....

        www.parasiticsanalytics.com

        TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/

        Comment


          #5
          Sorry again late reply it was the stock regulator mounted under the battery box so I swapped in a combined R/R from a 1980 CB400.
          1979 gs1000e (everyday) 1977 gs750 for sale
          1983 yam xj550 maxim streetbob sold
          1995 gsx750F everyday fighterjet 1990 gsx1100F for sale
          2000kaw zx600
          2003 BMW K1200GT sport tour
          2000Buel Cyclone M2 motorwork
          1984 Yam venture xvz1200 -long ride/cold ride ride gf ride..
          1978 Honda cb750F3 supersport top end (still)
          1976 Harley FL 3/8" S&S stroker - motor out way too long
          1980 Harley fxs80 - wacked good on this one

          Comment


            #6
            Find a rotor and matching stator from a later gs550, 18 pole instead of 12.
            My bikes 79 GS1000 1085 checked and approved by stator the GSR mascot and 77 GS750 with 850 top end, GS850g, and my eldest sons 78 GS550, youngest sons GS125. Project bike 79 GS1000N

            Comment


              #7
              Make sure all your grounds are good, clean and tight. I still have my completely stock charging system on my 77 750 with no issues. But I've added/replaced most ground cables with stereo power cables. Don't go cheap or buy some wonderful walking shoes...!
              Current:
              1993 ZX11 - 2nd build in progress
              1977 GS750 (710 is getting closer)
              1998 Kawasaki Voyager - selling
              1998 Chevy C2500
              1999 Rav4

              Comment


                #8
                The grounds on these bikes or really bad. A lot of Suzuki batteries ground to the engine, and they ground onto a painted surface, relying on the threads to provide ground. This causes the bolt to ground, and then your bike has a floating ground, which causes many many problems. Do what Nessism​ suggests, and make sure your grounds are good. If it is going to the engine, file that spot to bare aluminum to get a good ground. Check all grounds.

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