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    transmission grinding

    hey guys. bumbling my way through my second GS, this one an 82 850 G (L?) I picked up living in Quebec.

    was my only ride last fall and this summer, and served me well on my recent move back to Louisiana. two weeks later, though: grinding.

    first noticed tues morning, thirty seconds from work: a grinding noise/sensation below to my left, most prevalent when not revving, when I was decelerating on engine braking. I feel like it was even slowing me down.

    being outside work, I had no time to diag, and was hoping to credit the situation to my vehicle hypochondria

    after work, five mile ride home in moderate traffic, it proved to be the real deal. was almost imperceptible at first, but I was revving high till i got closer to my downtown apartment.

    pulled rear brakes off optimistically hoping it was just a caliper seized (happened to me before). no dice.

    drained gearbox (thanks for the site, basscliff): very low, but no shavings to speak of, in the oil or the magnet. refilled, let it soak, ran in neutral some, still same problem.

    drained and refilled again. this time some minute shavings came out the overfill hole, nothing that seemed extraordinary for a 30 year old bike.

    checked differential oil on the shaft, was crystal clear, maybe even a little overfull.

    the boot over the... ujoint? what's it called? had a tear, but inside looked clean.

    ran it through gears on the center stand with no rear wheel, seemed... fine. no noises anywhere in the range.
    same with the swingarm and driveshaft removed. nothing to get worried about audible, and hand on the gearbox felt no grinding.

    BUT there was definite recent scoring on the front end of the swingarm, where the turning driveshaft hit, metal on metal, the swingarm. I have pics to illustrate, will post them when I can het to a desktop PC (recently in town, no internet in our place yet).

    so that is superfresh, and I'd want to blame the problems on that. but... my pal thinks we can't know we didn't cause that ourselves when running it on the stand the first time... the scoring happened on the bottom side of the shaft opening, presumably because the shaft was angling too downwards. I can't contribute, I was manning controls and feeling the gearbox while he was eyeing the bearings in the differential. neither of us noticed any noises or jerking I thought we would have if we were witnessing an unrestrained swingarm getting eaten into by its driveshaft, so (maybe optimistically) I am wanting to blame my highway noises/grinding/drag on a collision of the shaft and swingarm.

    but even that doesn't make total sense to me. in regular operation, how would they have touched? in the teardown, I hadn't seen anything indicating the swingarm was angled too downwards.

    toss me ideas. I suspect if no-one has clues, tomorrow's steps will be taking the engine out and pulling the gearbox off. which I dread.

    my pal suggest bringing my rear wheel and differential to a shop to have them inspected. i'm skeptical, I really felt the noise and grinding vibes were coming from my side, not behind me. also local dealership mechanics seem to treat their customers with (at best) mild derision.

    #2
    The problem is likely the secondary drive -- the set of bevel gears at the left rear of the engine.

    There are two likely failures -- the bearing that holds the output shaft/flange is one, and sometimes the flange or the retaining nut breaks off the output shaft.

    Take a look at the u-joint and wiggle the shaft around -- if it can move around, which I suspect is your problem, the bearing in the output is stuffed.

    The simplest solution is to buy a used output gear and bearing (they pull out as a unit) from another 82-83 GS850 (79-81 are very slightly different). This can be removed and replaced with the engine in place, but it's a tight fit. You may have to loosen the engine mounting bolts and do a bit of prying. Removing the swingarm is fairly easy on a shaftie, but make sure you get it centered correctly when you put everything back together.


    That bearing is #7 on this diagram.
    Last edited by bwringer; 09-08-2012, 11:05 PM.
    1983 GS850G, Cosmos Blue.
    2005 KLR685, Aztec Pink - Turd II.3, the ReReReTurdening
    2015 Yamaha FJ-09, Magma Red Power Corrupts...
    Eat more venison.

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    Comment


      #3
      Do NOT take your friends advice and let anyone other than you service your bike. You're the right person for the job, you charge the fairest rates, and you will do it properly with the help of a manual, and the wealth of information on this forum. A dealer will only screw you over in price and quality of work.

      Comment


        #4
        thanks for the tips and motivation guys

        regarding wiggle in the drive: I woke up needing to pee, checked this thread, couldn't wait till morning.

        already have the shaft and ujoint removed, so I grabbed hold of the output (#10?) and shook.

        not a lot of play in it. I'd say millimetres, if anything.

        but it is some. and looking at the gearbox I'd guess removing the output and bevel gear is just 8 bolts and some prying, like you said. will take them out in the am and get my eyes on them

        Comment


          #5
          Not too much prying, the aluminum housing of the can break. Loosen some of the engine case bolts in that area to lessen the pressure and they come out alot easier

          Comment


            #6
            Please inspect the bearings (#2 in fiche in post #2 of this thread).
            That entire unit comes out. (Not easily.)
            And read this thread: http://www.thegsresources.com/_forum...+fifty+feet%21

            Eric

            Comment


              #7
              i recently had secondary drive failure. it started last riding season as an almost imperceptible hum or whine which changed with drive rpm's and load. of course i put off dealing with it until one day when it became a very loud knocking sound. (the gs did get me home!).

              the nut #12 and end of shaft #1 had broken off. bearings in both units were shot. i'm tempted to think the bearing in the first unit went bad causing the gears to mesh incorrectly (they have to be carefully adjusted when installing) which caused the output unit to fail.

              definitely loosen the case bolts that squeeze the drive units. they should go in and out fairly easily, eventually, because there is a lot of shim adjusting when it's time to put it back together. i think there are 7 case bolts that affect.

              i took some pictures of the repair job. if you think any of them might help i can post a couple.
              2002 bmw r1150gs 1978 gs1000E skunk les pew 1979 gs1000L dragbike
              82 gs1100L probably the next project
              1980 gs1000G the ugly 1978 gs750E need any parts?
              https://m.youtube.com/watch?v=m_m2oYJkx1A
              1978 gs1000E skunk #2 RLAP
              https://live.staticflickr.com/65535/...2f1debec_t.jpg

              Comment


                #8
                started getting the gears out. working on the rear/output gear first. got it loose (loosened nearby bolts, thanks for the tip), but it is running into the frame before I can slide it all the way out. my eyes can't see how to get it out without moving the entire engine an inch to the right (or remove). pointers?

                Comment


                  #9
                  Take a good inspection of the sprockets and chain also. Worn gears and stretched chains dont mesh well after a while and bind and make grinding noises also. Hope your not doing all this work for just some worn chain or gears.
                  MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                  1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                  NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                  I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                  Comment


                    #10
                    remove all motor mounts except the front long bolt. the motor can pivot on that. then you can pry the motor up so the rear unit will come out.
                    2002 bmw r1150gs 1978 gs1000E skunk les pew 1979 gs1000L dragbike
                    82 gs1100L probably the next project
                    1980 gs1000G the ugly 1978 gs750E need any parts?
                    https://m.youtube.com/watch?v=m_m2oYJkx1A
                    1978 gs1000E skunk #2 RLAP
                    https://live.staticflickr.com/65535/...2f1debec_t.jpg

                    Comment


                      #11
                      Originally posted by chuck hahn View Post
                      Take a good inspection of the sprockets and chain also. Worn gears and stretched chains dont mesh well after a while and bind and make grinding noises also. Hope your not doing all this work for just some worn chain or gears.
                      His bike is a shafty.

                      Comment


                        #12
                        Ohhh.... didnt really look for year or model in his sig....mine are all chain and thats one of the things chainers do when they are worn out.
                        MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                        1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                        NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                        I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                        Comment


                          #13
                          Originally posted by chuck hahn View Post
                          Take a good inspection of the sprockets and chain also. Worn gears and stretched chains dont mesh well after a while and bind and make grinding noises also. Hope your not doing all this work for just some worn chain or gears.
                          I know I'm risking sounding pretty dumb here, but I'm confused enough to warrant it:

                          on a shaft drive?

                          pressing on, I got the side gear out... and it looks pristine. how freely should these bearings spin? this one doesn't seem to have rough spots, but doesn't fly loose as a bicycle wheel, either

                          removed most if the recommended engine mounts, except the most crucial: the one below the gearbox. I need some Allen wrenches to get off the foot peg that is stopping me from getting that long bolt out. with it loosened, only getting a little lift out of the engine.

                          will update later after a trip to harbor freight.

                          Comment


                            #14
                            Originally posted by chuck hahn View Post
                            Ohhh.... didnt really look for year or model in his sig....mine are all chain and thats one of the things chainers do when they are worn out.
                            lol gotcha sorry typing crazy slow on my cell

                            Comment


                              #15
                              the bearings: they should turn smoothly. you may not be able to feel any play but if they have any roughness while turning they're probably shot. they probably won't spin freely though. mine felt like there was sand in them.
                              2002 bmw r1150gs 1978 gs1000E skunk les pew 1979 gs1000L dragbike
                              82 gs1100L probably the next project
                              1980 gs1000G the ugly 1978 gs750E need any parts?
                              https://m.youtube.com/watch?v=m_m2oYJkx1A
                              1978 gs1000E skunk #2 RLAP
                              https://live.staticflickr.com/65535/...2f1debec_t.jpg

                              Comment

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