R100GS: General Maintenance

Discussion in 'Airheads' started by montblanc97, Aug 3, 2020.

  1. montblanc97

    montblanc97 Been here awhile

    Joined:
    Jun 19, 2012
    Oddometer:
    240
    Location:
    Cleveland, Ohio
    Hi Everyone-
    I'm still quite new to airheads and was wondering what people recommended as general maintenance for my 89 R100GS. I am planning to lubricate splines, but I also heard that one should lubricate the swing arms as well. What lubricant would you recommend using?

    Secondly, when do most people have their transmission rebuilt? My transmission only has 34k miles on it; however, the bike has been sitting for over 20 years.

    Lastly, someone recommended upgrading & replacing the valve guides since the late 80s GS's had extra room for valves. Is this smart to do?

    Is there any other general maintenance that you would recommend doing on an airhead?
    #1
  2. Mark Manley

    Mark Manley Long timer

    Joined:
    Apr 3, 2010
    Oddometer:
    2,561
    Location:
    Wessex, England
    For general servicing follow the book, if you don't have one get a Haynes or Clymer manual and follow the schedule, the swinging arm bearings in the paralever are sealed and cannot be lubricated unlike the earlier ones but given the mileage of yours should have plenty of life left in them.

    That is still pretty low mileage, many reach 100,000 miles without attention, mine has done 175,000 without any, I would recommend changing the oil with a good quality EP80/90 gear oil every 5,000 miles, if when you drain the oil it is milky refill with a cheap one and change again after a few miles and repeat until it comes out clear. Some people think if the bike is of the period when no circlip was fitted on the output shaft there is a potential problem and the gearbox should be rebuilt to install one, I do not subscribe to this theory.

    No idea where this came from but if the bike is running well, has good compression and not using excessive amounts of oil this is totally unnessessary, the original BMW parts are high quality.

    Rebuilding the carbs with new seals, gaskets, needles and jets would be a good idea at that mileage, you could also remove the sump plate and give it a clean inside taking a look at the oil pick up strainer and if you are feeling like getting inside of it removing the gearbox and lubricating the clutch splinds would be a good idea.
    #2
  3. nobbylon

    nobbylon Long timer

    Joined:
    Aug 13, 2012
    Oddometer:
    1,178
    Fix the gearbox when it groans or breaks! fresh oil every year. I change oil and filter on mine every 2k miles but it’s rare i’ll do those miles at all so oil yearly. Same with bevel and shaft...once a year. Get a grease gun attachment and just squirt normal grease into the swing arm pivots until fresh grease comes out. Easy. Head bearings are a bit harder but I just put on centre stand and undo the top triple and drop the whole front end until tyre hits ground. Clean and grease. I change brake fluid every 1-2 years dependant on my memory. There’s specific GS questions there so i’ll leave those to the guys that know them.
    #3
    montblanc97 likes this.
  4. Mark Manley

    Mark Manley Long timer

    Joined:
    Apr 3, 2010
    Oddometer:
    2,561
    Location:
    Wessex, England
    Not on a paralever GS, the hole through the pivots goes straight into the swinging arm which runs dry and this will not lubricate the bearings which are sealed.
    #4
    montblanc97 likes this.
  5. nobbylon

    nobbylon Long timer

    Joined:
    Aug 13, 2012
    Oddometer:
    1,178
    Roger
    #5
  6. montblanc97

    montblanc97 Been here awhile

    Joined:
    Jun 19, 2012
    Oddometer:
    240
    Location:
    Cleveland, Ohio
    What about the transmission circlip? Was that installed on the 1989 model? If not, is it recommended to add it at 34k miles?
    #6
  7. montblanc97

    montblanc97 Been here awhile

    Joined:
    Jun 19, 2012
    Oddometer:
    240
    Location:
    Cleveland, Ohio
    What kind of grease would you recommend?
    #7
  8. tennessee thumper

    tennessee thumper Long timer Supporter

    Joined:
    Nov 3, 2007
    Oddometer:
    2,238
    Location:
    Arkansas Ozarks
    MB 97,

    There are any number of areas that need regular attention on your bike.

    I would start by lubing pivot points on all the cables with a quality grease.
    Make sure your valves are correctly adjusted and your throttle and choke cables have proper free play.

    If you can source one of these, either hard copy or online, I recall there is a general maintenance guide and schedules for your model.
    bmw-r80gs-r100r-service-manual-21215b320096-page1.jpg

    Don't worry about your valves and transmission now unless either are exhibiting performance issues.

    One thing you can do to expand the life of the transmission is regular oil changes and make sure no water gets in thru the boot at the top where the speedo cable goes in.

    Assuming you have the bike for a while and it's trouble free ---a circlip might be a winter time job down the road for a specialist when you are off for the season.

    Valves on your GS should not need attention, early mid 80s were the issue.
    #8
    montblanc97 likes this.
  9. Mark Manley

    Mark Manley Long timer

    Joined:
    Apr 3, 2010
    Oddometer:
    2,561
    Location:
    Wessex, England
    I am not sure if it was but as I mentioned in my first post do not support the idea that it is worth spending $$$$ on rebuilding a gearbox to rectify a problem that will probably never happen. I am not sure how many people on this forum actually have first hand experience of no circlip causing a problem, I have only ever seen one person here say they have had a failure in all of the dozens of bikes and millions of miles travelled and have never heard of any bike here in the UK with no circlip causing a problem.
    Using a GL4 gearbox oil rather than GL5 is favoured in the gearbox and final drive.
    You can use any general purpose grease for headrace bearings and other grease points, the gearbox/clutch/shaft splinds require a special grease the details of which I forget but am sure someone will be along with the correct grade.
    For engine oil a 20/50 for vintage engines is most popular and there is a whole thread about it here with a mixture of helpful information and disagreement.
    https://advrider.com/f/threads/mc-oil-thread.1391868/
    #9
    airheadPete and montblanc97 like this.
  10. Andy FitzGibbon

    Andy FitzGibbon Been here awhile

    Joined:
    Aug 14, 2018
    Oddometer:
    183
    Location:
    26283
    The rocker arm bearing cages in my 1993 PD all started failing around 35k miles. It's a known problem... apparently some batches of bearings are worse than others. Watch for that when adjusting valves. Once the cage fails, the rollers can work their way out of the rocker arm and through the slot in the rocker block. If that has happened, one or two will probably fall out when the valve cover is removed.

    When you lubricate the driveshaft splines, you should also inspect the shaft itself for bad u joints or slippage at the rubber cushion coupling (observed by comparing whether or not the u joint yokes are parallel to one another). Both are not replaceable in their factory form. Henderson Precision can rebuild the shaft for replaceable joints, and Ted Porter offers a brand new shaft with replaceable joints and rebuildable cushion coupling.

    The drive splines require grease with a high molybdenum content, available from a few sources (Honda and Ted Porter spring to mind... there are other options).

    If you have the Valeo starter, they are known for magnets coming unglued from the inside of the housing. Doesn't happen to all of them, but something to be aware of. Several replacement options are available... new Valeo (supposedly with the problem fixed), new Bosch, imitation Valeo, and Nippon Denso (Toyota) adapted with a custom nose casting.
    #10
    montblanc97 likes this.
  11. AntonLargiader

    AntonLargiader Long timer

    Joined:
    Aug 28, 2003
    Oddometer:
    6,769
    Location:
    Charlottesville, VA
    Those of us who fix transmissions see plenty of "circlip problems" and the decision to pre-emptively repair is really a function of time and money. If you aren't going to be doing big trips and you can take the bike out of commission whenever a problem arises, then you can put it off. If you're trying to make the bike really right and you have the budget, do it now.

    I don't think this is what you were actually asking about, but upsizing the intake valves from 42mm to 44mm is/was mostly a European thing IMO. I don't think it was ever that big here. The early 30° exhaust valves tend to be loose in the guides from new and can be noisy as early as 20,000 miles. BMW even sold a repair specifically for that problem: valves with 8.3mm stems and a matching reamer. I replace them with 45° valves and new guides of course.

    The loose valve guides, the lack of circlip, the gray crack-o-matic coil and the starter motor magnets are the inherent flaws of that bike, all of which are fixable.
    #11
    Plaka, montblanc97 and WooPig like this.
  12. abhiram

    abhiram Been here awhile

    Joined:
    Jul 24, 2018
    Oddometer:
    155
    Location:
    Oakland, California
    While I can't speak for long-term maintenance, here are a few things I had to take care of in the last six months or so. My bike is a 88 r100gs with 45k miles or so. I picked it up last year in December.

    I replaced the cables, coils, rubber boots etc. New motor and transmission oil. I lubed the splines as well. My drive shaft looked okay and I didn't find any play in the uj's.

    My bike wasn't perfect to begin with, so I had to address a leaky main seal.

    During this I also dropped the oil pan as I my old oil pump had sucked in some metal scrapings during its long life. After a new oil pump(rotors and cover), things are much better.
    #12
  13. Andy FitzGibbon

    Andy FitzGibbon Been here awhile

    Joined:
    Aug 14, 2018
    Oddometer:
    183
    Location:
    26283
    Since I'm in the middle of this job, here's a photo of how the rocker arm bearing cages fail. These are out of the same rocker. The obviously failed one was on the bottom, and the one that's just starting to crack was on top.

    Check yours often, and, if one goes, replace all eight. Emerald Isle sells replacements that are a good bit cheaper than BMW. 20200805_082307.jpg
    #13
    abhiram likes this.