Back home, back on the airhead !

Discussion in 'Airheads' started by airhead_irl, Oct 4, 2021.

  1. airhead_irl

    airhead_irl Airhead addict

    Joined:
    Jan 20, 2010
    Oddometer:
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    G'day people,

    Despite checking in from time to time, it has been over a year since I posted any content of my own. I think that was when I did a bit of a cosmetic tidy on this....

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    Not long after I finished up that little episode with the R100, my partner and I departed our home in Ireland to travel as far as we could during the pandemic in our VW campervan. It was an interesting 13 month trip that saw us notching up 42k kilometres around Europe and the Asian side of Turkey. We met many great people, saw many wonderful and weird places while opting to stay in the "wilds" as much as possible.

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    Returning home was a strange affair but getting back on the bikes helped that transition ! I had stored the bikes with fully charged batteries (disconnected) and with fresh engine oils before leaving. Starting the bikes went well and all seemed good so a few short day trips were in order to get back into the swing of things.

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    While we were travelling, I had been giving thought to doing a few upgrades to the R100GS for long distance travel, luggage specifically. I looked at and considered various options but always hankered after a set of genuine BMW Touring cases: they look tidy and they are light. Scouring the German classifieds these turned up and I had them delivered home....

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    The cases were in fantastic condition and very reasonably priced. Yay.
    Whilst out on another day trip, I noticed a weird vibration while on the way home. It seemed to be most noticeable in 4th and 5th gear.

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    The vibration reared its head not long after this photo stop

    Rotating the rear wheel by hand in both directions has not revealed any grating noises or clunks. It was quite smooth in fact. So, maybe it's carb sync or something more sinister like the gearbox. Or maybe it's nothing and I'm just losing my mind (very possible). Anyway, I have decided to give the bike a going over for peace of mind and hopefully nothing too nasty pops up in the process. But that might be boring, mightn't it ?!

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    One thing that I also noticed was that the throttle cable adjustment screw on the right hand carb never seemed to have that much adjustment before it ran out of free play. I disconnected the cables to make sure the shorter one was going to the left hand side and it appeared to be. I must pay more attention to cable routing upon reassembly.

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    Some changes may occur along the way, such as replacing these with black items....

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    .....and replacing the Hagon damper with something like a YSS replacement:

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    Other items for consideration are the front brake - a new stainless hose and possible a 320mm swap. Four piston calliper ? Maybe.

    More to follow....
    #1
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  2. bmwrench

    bmwrench Long timer Supporter

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    I'm confused. Were is home?
    #2
  3. Kiwiabbo

    Kiwiabbo Long timer

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    70709D7B-7F86-4E4B-B4EB-E1FD9163E54B.jpeg I quite like the later k style bags. Plenty of room and they feel snug on the z rails. I put on a low pipe so have two full size bags. Run a YSS shock and am very happy with it.
    #3
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  4. airhead_irl

    airhead_irl Airhead addict

    Joined:
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    Eire (Ireland)
    Oops, I should have mentioned that ! Home is southern Ireland, Cork to be exact.
    #4
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  5. airhead_irl

    airhead_irl Airhead addict

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    That's quite a smart looking setup. I believe your approval of the YSS in the past is one reason I decided to consider the brand in the first place !
    #5
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  6. airhead_irl

    airhead_irl Airhead addict

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    I had an hour to pass earlier so I drained the gearbox and final drive oils. The FD oil and drain plug looked fine but the gearbox drain plug looked more fuzzy than I would have thought.

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    I blotted the excess oil off with tissue paper and it looked more like a normal "paste".....

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    Being a clown, I never inspected the clear container before draining the oil into it. Therefore, I cannot be sure if this debris is actually from the gearbox or from elsewhere....I really owe myself a slap.

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    So, I will fill the gearbox up with fresh oil, ride a few hundred miles and inspect again :becca
    This GS happens to be a '91 year bike with 115k kilometers (71k miles).
    #6
  7. bmwrench

    bmwrench Long timer Supporter

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    The rear bearing on the output shaft is likely failing. I'm sorry to tell you that.
    #7
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  8. airhead_irl

    airhead_irl Airhead addict

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    I've not replaced this part before. Is it a PITA to replace ? Perhaps that accounts for the vibration felt.
    #8
  9. bmwrench

    bmwrench Long timer Supporter

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    The gearbox has to be disassembled. The problem is caused by the lack of a snap-ring at the front of the shaft, coupled with a sealed bearing at the rear. I've pried the seals off those bearings to find them dry.
    #9
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  10. airhead_irl

    airhead_irl Airhead addict

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    Most informative and many thanks. Hmm, new adventure ahead of me then.

    So the infamous circlip issue. Also, am I wasting my time filling with oil and reinspecting after a long ride or should I just pull the gearbox and "have at it" ?
    #10
  11. airhead_irl

    airhead_irl Airhead addict

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    Despite both being dark coloured (tranny oil)....

    Guinness tastes better.....
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    #11
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  12. bmwrench

    bmwrench Long timer Supporter

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    If you have the time and ambition, I'd just get in there.
    #12
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  13. MonzaCross

    MonzaCross When life throws you a curve, lean into it

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    Thanks for catching us up. Some great adventures all around there.
    #13
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  14. bmwrench

    bmwrench Long timer Supporter

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    To expand upon this, if I didn't have the measuring tools, I'd cheat, and just replace the bearing.
    #14
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  15. greentreephrog

    greentreephrog Been here awhile

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    'Wrench,

    I have an '84g/s (August '83 build, as I recall), so I think I'm thankfully free of the circlip issue. However your replies got me wonderin' - just replacing the bearing without remedying the lack of circlip? Would that not simply repeat the original issue? Also, I have a newly-restored backup gearbox, but I'm not sure what vintage - is there any information as to what gearbox serial numbers (just below the LH exit from the plastic air filter casing) are more or less likely to have a circlip installed from original?

    GTP
    #15
  16. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    It sounds like you head out on long trips so if the tranny needs to come apart, you might consider adding a taller 5th gear for cruising.

    For brakes, a braided stainless line, 320 rotor or EBC floating front brake rotor with a Harrison 6 piston caliper are all good upgrades.

    Also LED tail light inserts for safety and VISIBILITY.

    Great pictures too. Looks like you made a great choice to travel!
    #16
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  17. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    Depending on the bike history, without a service history, you really don't know if the tranny has been rebuilt or replaced sometime in the past..or if it was rebuilt, was the circlip added or not, or a tranny with the circlip installed for one without.

    When shifting gets hard ..or like this one, a strange vibration hits, just put it down to time to pull it apart and check the drive shaft while you're in there...

    Remember some trannys without the circlip will work just fine for 100K miles because of good maintanance, fluids changes, and little off road stress...others only lasted around 40K miles and rebuild time.
    #17
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  18. bmwrench

    bmwrench Long timer Supporter

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    Snowbum was working on a list of 'boxes without or with snap-rings. It's a tall order.

    Replacing the rear bearing without adding a snap-ring might be a temporary repair, but aren't they all. :)
    #18
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  19. airhead_irl

    airhead_irl Airhead addict

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    Thank you kindly sir !

    That actually is encouraging because I have been researching the work since you enlightened me as to the issue. And you're correct - the tools I do not have. However, I'm kinda thinking I should just remove the transmission covers and see what is what as regards the other bearings.
    Now, I'm not one for rash decisions so I am still considering my options !

    It was a big risk to travel but it turned out to be a fantastic time for travel really. I can't say we really encountered any negatives. Except getting ejected out of Bosnia by the police.....but that's another tale.
    Thanks for the advice - duly noted !
    #19
  20. airhead_irl

    airhead_irl Airhead addict

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    Somebody recently stated on another thread recently (about diaphrams ?) that, here in this forum, it is akin to sitting around the campfire and shooting the breeze....over a beer or two hopefully. So to stoke the fire and keep the chat going.....

    I gave the gearbox issue more thought (and killed off many brain cells) and decided that if it's going to be done, it should be done correctly i.e. bearings replaced and circlip groove cut (assuming that it's not already done). But not having any of the "oddball" tools required for the job and no resource to cut the circlip groove, I entrusted the bike to a local and long time airhead mechanic that has done the job many times. Not very adventurous of me but I'm all for the easy life these days :D
    So that freed up some time to revisit the R100. This was the subject of another thread about 400 years ago....

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    Just like the GS, this had been laid up for over year but it didn't look so bad at all and just needed some dusting down and a few very minor tweeks. The horn bracket on the RHS had broke a while back so I doubled up on them like a good inmate suggested on here at the time.

    Horn brackets are plentiful around my garage....
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    Ireland is blessed with an abundance of damp air.....the joys of living on a rock out in the Atlantic and all that jazz. As a result, parts of the bike had white oxidization such as this....

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    No big deal I thought. But light traces remained even after some elbow action. I eventually got there though. This was after the first attempt:

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    The front brake needed a quick bleed and that was about it. I just need to pay the annual tax now and then it can legally do its thing around Irish roads.

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    Being happy my lot for now, it was time for some local nutrition.....

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    #20