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    #1

    Crankshaft bearings

    My 82 GS1100EZ (37,500 miles) has a bad bearing sound that has been isolated to the front left of the crankcase. Its not the starter or clutch or transmission.

    I have a factory service manual and it doesn't cover the crankshaft much. Schematics on bikebandit.com looks like the crankshaft itself comes apart to allow installation of the bearings and lower conrods.

    I've had the engine apart down to the base gasket before and think I'm mechanically minded enough to get to the crank and get it out.

    Has anybody ever replaced crank bearings? Is it something a reasonably mechanically minded person can do? Is it difficult to get the crank itself apart and back together? Will I need a press?

    Or . . . does the crank need to go to a shop, and if so, is it prohibitively expensive?

    Thanks for any advise any of you can give.
    Tags: None
    #2
    Case splitting time... If you remove the spark plug wire when it is running does the noise change pitch or go away? IF not, it might be something else. But if your sure, get an engine gasket set and take it out. You might have to get the crank welded, sometimes they twist up. Ask the 1150 gurus here about the best course to take, another running engine may be cheaper and you could part out your old one
    1981 GS650G , all the bike you need
    1980 GS1000G Power corrupts, and absolute power corrupts absolutely

    Comment

      #3
      Never tried pulling a spark plug. What would be the problem you're looking for by doing so?

      The noise is very distinctive and sounds like a bad bearing. Had another guy listen to it who has worked on a lot of m/c and jetski motors (not a pro) and it definitely sounds like a bad bearing to him.

      Comment

        #4
        You need a press to take it apart & put it together THE ALIGNMENT IS CRITICAL You are talking $500-800 to have it rebuilt

        Comment

          #5
          crank

          The only way that it is the crank is if you got forceful removing a wrist pin, when you had the top end off, or you really beat the bike, and I mean hard, the noise you will get if its a main bearing is a rumbling noise, the outer bearings can be replaced with out taking the entire crank apart. I would pull the stator cover and check for broken magnet material in the rotor, witch would give a grinding and scraping noise

          Comment

            #6
            Before I started tearing the engine down. I would remove all four plugs, drain the oil and remove the oil pan and take the ignition cover plate off the right crank end. Then I would lay under the bike and turn the crank by hand. Usually, you can feel and hear a bad bearing as you spin it. It will give you one more chance to confirm the problem before a teardown.

            Earl


            Originally posted by stasch
            Never tried pulling a spark plug. What would be the problem you're looking for by doing so?

            The noise is very distinctive and sounds like a bad bearing. Had another guy listen to it who has worked on a lot of m/c and jetski motors (not a pro) and it definitely sounds like a bad bearing to him.
            Komorebi-The light filtering through the trees.

            I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

            Comment

              #7
              Bad crank bearing on an 1100? Only if the bike has been beat to within an inch of it's life all through those 37,5k miles. I would doubt it, but it's possible. The crank bearings on these bad boys are just about the most overbuilt the world has ever seen. You said starter and clutch, but are you sure it's not the starter clutch? That would make more sense to me.

              SqDancerLynn1 Posted: Thu Jul 28, 2005 6:44 am Post subject:

              --------------------------------------------------------------------------------

              You need a press to take it apart & put it together THE ALIGNMENT IS CRITICAL You are talking $500-800 to have it rebuilt
              I'm assuming this is a price to have it welded and balanced as well, right? They must have to do that anyway.
              Currently bikeless
              '81 GS 1100EX - "Peace, by superior fire power."
              '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

              I ride, therefore I am.... constantly buying new tires.

              "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

              Comment

                #8
                I'm with Jethro on that one. The starter clutch is MUCH more likely to be the cause.

                Earl


                Originally posted by Jethro
                The crank bearings on these bad boys are just about the most overbuilt the world has ever seen. You said starter and clutch, but are you sure it's not the starter clutch? That would make more sense to me.

                SqDancerLynn1 Posted: Thu Jul 28, 2005 6:44 am Post subject:

                --------------------------------------------------------------------------------

                You need a press to take it apart & put it together THE ALIGNMENT IS CRITICAL You are talking $500-800 to have it rebuilt
                I'm assuming this is a price to have it welded and balanced as well, right? They must have to do that anyway.
                Komorebi-The light filtering through the trees.

                I would rather sit on a pumpkin and have it all to myself than be crowded on a velvet cushion. H.D.T.

                Comment

                  #9
                  It you send it out for repair they will most likely tear down the whole crank and may find other problems. It's not cheap by any means.

                  If it's a bearing I would guess the connecting rod.
                  1166cc 1/8 ET 6.09@111.88
                  1166cc on NOS, 1/8 ET 5.70@122.85
                  1395cc 1/8 ET 6.0051@114.39
                  1395cc on NOS, 1/8 ET 5.71@113.98 "With a broken wrist pin too"
                  01 Sporty 1/8 ET 7.70@92.28, 1/4 ET 12.03@111.82

                  Comment

                    #10
                    My GS850 also has a noise coming from the left side that sounds like bearing noise. I've heard the crank bearings on this engine are almost bullet-proof, so I have assumed it's something else. Also, it seems to me that roller bearings wouldn't 'knock' the same as plain bearings.

                    It has gotten no worse over the 1000 miles I've had the bike. It has 35K miles. I'd like to determine if I should worry about it or let it go. The noise is noticeable, but not that loud.


                    Ace.

                    Comment

                      #11
                      One thing people don't realise. OUR GS engine are air cooled and can be very noisey at idle What does it sound like at 3K rpm????

                      Comment

                        #12
                        SqDancerLynn1 Posted: Thu Jul 28, 2005 6:22 pm Post subject:

                        --------------------------------------------------------------------------------

                        One thing people don't realise. OUR GS engine are air cooled and can be very noisey at idle What does it sound like at 3K rpm????
                        Glad someone else said it. When I got my 81 1100E I swore it was on the brink of total self destruction due to the obscene noise of the motor at idle. That was 30k miles ago...
                        Currently bikeless
                        '81 GS 1100EX - "Peace, by superior fire power."
                        '06 FZ1000 - "What we are dealing with here, is a COMPLETE lack of respect for the law."

                        I ride, therefore I am.... constantly buying new tires.

                        "Tell me what kind of an accident you are going to have, and I will tell you which helmet to wear." - Harry Hurt

                        Comment

                          #13
                          Originally posted by SqDancerLynn1
                          One thing people don't realise. OUR GS engine are air cooled and can be very noisey at idle What does it sound like at 3K rpm????
                          That's music to my ears at 10K 8)
                          1166cc 1/8 ET 6.09@111.88
                          1166cc on NOS, 1/8 ET 5.70@122.85
                          1395cc 1/8 ET 6.0051@114.39
                          1395cc on NOS, 1/8 ET 5.71@113.98 "With a broken wrist pin too"
                          01 Sporty 1/8 ET 7.70@92.28, 1/4 ET 12.03@111.82

                          Comment

                            #14
                            If there's no knock at 3K RPM, does that mean everything is OK with the bearings? I don't hear anything at that RPM.

                            Comment

                              #15
                              If it is smooth Running at 3K rpm, don't worry about it.. After you have owned your bike for awhile you will get used to the noise & will be able to Identify strange noises from normal ones

                              Comment

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