1989 R100GS Project Questions

Discussion in 'Airheads' started by montblanc97, May 24, 2020.

  1. montblanc97

    montblanc97 Been here awhile

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    Hi Everyone. I recently purchased a 1989 "Powder Blue" BMW R100GS. The bike is in good cosmetic shape, but it has been sitting for over 20 years. It has 34k miles on it. I'm looking to make this my "perfect" everyday bike; however, I'm still a novice mechanically speaking.

    As I plan to replace many of the parts on the bike, what are some common problematic areas that I should look over? What are some good modifications to make to this bike (i.e., Enduralast charging system, Ohlin Shock, Breaks, Etc.)? Would you guys recommend getting a stainless steel brake line? If so, where would I be able to find one?

    Where is the best place to find parts for the R100GS? I will need filters, fuel lines, brake lines, seals, brake pads, and other things.

    Sorry for all of the questions. This is my first big project and I'm quite anxious to get started!!
    #1
  2. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    Start by making it run, skip everything else until you know it runs well.

    Drop the oil pan first and clear it out
    Rebuild the carbs completely
    Clear out the tank, rebuild the petcocks
    adjust the valves
    throw in a battery and fresh fuel and see what it does.

    Then, change the transmission oil, if it is cloudy you may have a water issue.
    #2
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  3. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    #3
  4. akabeton

    akabeton Adventurer

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    As above.

    You should probably get a new oil pan gasket but hold off on the other stuff.
    Be careful reinstalling the pan, it’s easy to strip the threads.
    Pick up a Clymers or Haynes manual, handy to have. The BMW manual can be found in PDF format several places on line.

    Parts when needed are readily available, depending on your location.
    Post some pics, we like that.

    Lots of great folk on here.
    #4
  5. mslim

    mslim Long timer

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    #5
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  6. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    I think that bmw-parts-bit is Boxerworks in GA
    #6
  7. montblanc97

    montblanc97 Been here awhile

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    Thanks everyone for responding to my thread. I will post some pictures of the bike and keep you updated with what I find.

    Attached Files:

    #7
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  8. abhiram

    abhiram Been here awhile

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    Nice! Congratulations on the acquisition! I bought the 88 with the same paint scheme last year.
    Currently sorting it out as we speak. I have ordered most of the parts from Euromotoelectrics and Boxer2Valve.

    Here is a picture of mine when I bought it.

    On mine, I had to replace the coils as they were cracked. I'd second what folks said above. Drop the oil pan and see where you are at. I am planning to do that this week :)

    Good luck!

    Attached Files:

    #8
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  9. mslim

    mslim Long timer

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    Yep I believe it is.
    #9
  10. Texer

    Texer Been here awhile Supporter

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    Calling Big Bamboo, calling Big Bamboo....
    #10
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  11. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    You rang...? :D
    Here's an edited list by Tom Cutter of things I check on any new to me BMW, especially the ones that have been sitting awhile. Note some of these do not apply to the later models:
    1) Change ALL oils (including brake fluid). New fuel line!

    2) Torque cylinder heads (25 foot pounds, loosen each nut 1/2 turn,
    then torque, use crisscross pattern), adjust rocker arm end play (zero
    play, no rotational binding), adjust valve clearances (cold engine) to
    .006" Intake, .008" Exhaust.

    3) Service auto advance unit (don't snap the thread off the end of the
    cam, tighten GENTLY!), grease point cam felt with a smear of grease. (does not apply)

    4) Set points gap to 0.016" (0.40 mm) using a good feeler gauge, or
    better yet a dwell meter, look for 39 degrees on the four cylinder
    scale (gives you 78 degrees on a two cylinder). (does not apply)

    5) Set ignition timing static setting to S mark on flywheel.

    6) Check full advance timing is at 3200 RPM using a strobe timing light. The dot (or hole if the paint is gone) above the F mark should be steady in the center of the timing
    hole, aligned with the machined groove in the side of the hole. (Z mark on later models)

    7) Service the air filter, i.e., put a new one. DO NOT blow out air
    filter with compressed air, do not leave a K&N filter in at all.

    8) Drop carb float bowls and clean the tiny jet in the little well in
    the corner of the bowl using a single strand of wire from a wire brush,
    held with needle nose pliers. Make sure contact cleaner will spray
    through the jet into the bowl.

    9) Remove the main jet and jet holder (make a mental note of the depth
    of engagement of the jet holder), drop down the needle jet and emulsion
    tube, (keep your finger over the hole so they don't fall out and get
    lost.) Use some carb cleaner spray to clean the gunk that has
    accumulated above the jet holder. Spray the jets and emulsion tune
    clean, then reinstall the emulsion tube, needle jet and jet holder.
    Visually align the jets onto the needle carefully. As you screw the jet
    holder up in with your FINGERS, if it doesn't seat fully (remember the
    mental note?) then back it up about 1/32 of a turn and wiggle it as you
    screw it in gently (FINGERS ONLY!) You will feel when the emulsion tube
    finds its way up into the carb body hole. If you can't get it , remove
    the air tube from the air cleaner housing and visually see that the
    emulsion tube projects up into the venturi about 3-4 mm. You can wiggle
    the needle to help align it as you screw it up in with your FINGERS.

    10) Check the float level setting by lifting the float gently with your
    fingers. When the needle seats, BEFORE the spring loaded part begins to
    depress, the seam in the float should be parallel to the float bowl
    gasket surface. Reinstall the bowl carefully, making sure the gasket is
    fully seated in the groove all the way around. Use a new gasket.

    11) Check that the throttle cable has a tiny amount (1-2mm) free play
    when the throttle grip is all the way back. Get the two sides as close
    to the same free play as possible.

    12) Check that the choke cable fully seats the lever on the post when
    the lever is in the horizontal position. At half choke, the lever on
    the carb should be halfway between the posts. At FULL choke position of
    the hand lever, the choke lever should be all the way up to the top
    post.

    13) LIGHTLY screw the idle mixture screw IN until you feel the screw
    seat. Now back the screw OUT by 3/4 turns (this setting varies for
    other models).

    14) Turn the idle SPEED screw OUT until it does not contact the
    butterfly lever at all. Now screw the screw IN until it JUST touches
    the lever, now turn it IN one FULL turn. This will usually result in a too high idle speed.

    These are the baseline settings. Now take the bike for a LONG test
    ride, at least five miles, to get it to FULL operating temperature.
    Riding around the block or starting and revving on the stand will NOT
    work.

    At this point you need to synchronize the carburetors using vacuum gauges on the vacuum takeoff ports on the side of the carbs, or better yet, build yourself a manometer. Set the idle mixture on each carb at the point that gives best running, usually between 1/2- 1-1/4 turn out. Balance the idle speed screws, then balance the cable pull off idle. Recheck to be sure that you still have a tiny bit of free play of the cables. If not, readjust the cables.

    This should get the bike running pretty well. Idle speed should be
    at 1000-1100 RPM. DO NOT set the idle for a super low "tickover", as
    this will severely reduce oil circulation in the engine and make the
    transmission rattle like a bag of rocks. (edited 4/21/2020)
    #11
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  12. Mobiker

    Mobiker Long timer Supporter

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    "Powder Blue" :nah Nope. That's "Alpine White" :thumb

    All good advice. I'll reiterate the coil comment. If it still has the original "Crackamatic" coil it would be amazing. If does, change it. If its not cracked, it will be and you'll find out during Tropical Storm Bill in Shelbyville, Tennessee when it quits running in the rain. Not that I would know anything about that :augie

    I'll add that you need to check the diode board mounts. They're a rubber/steel sandwich and they crack in two or the steel parts delaminate from the rubber. This is going to be hard to tell for sure without removing the diode board unless more than two are already broke. Replace them with solid mounts. If you ever need a diode board I highly recommend Thunderchild. Quality board and class act.
    #12
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  13. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    weren't cracked coils for earlier bikes....like pre -84??


    trash that damned bra!!! and sell it to someone with a PD...LOL

    you're missing a clip for the brake line between the hard line and rubber line, it connects at the top of the fork leg..p/n 31 42 1 457 427
    and rubber grommet p/n 34 32 1 236 462

    29D291B3-DDBE-43C3-8E02-EF090253AE98.jpeg
    #13
  14. Mobiker

    Mobiker Long timer Supporter

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    Don't know about earlier bikes. My '88 came from the factory with a gen-u-wine Crackamatic.
    #14
  15. Mobiker

    Mobiker Long timer Supporter

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    Something else to check is the brake caliper function. It is not unknown for pistons to seize up in calipers after extended non-use.
    #15
  16. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    that won't be an issue.....it's getting better brakes..LOL....got him hook line and sinker...LOL

    but the MC????
    #16
  17. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    Welcome to a fun adventure. So many possibilites..everything from a good runner to a fabricated round the world traveler.

    Give me a call..too bad you're not in the Bay area. Currently have 4 G/Ss in the shop..one full frame up restoration, 2 for getting back on the road after 10 years sitting, and one for lots of upgrades to all the systems.

    Oh,,and 3 R80G/Ss being restored.

    So what are your plans when it's running? Heading for Canada or the Keys,,twisty roads with camping gear, 2 up or just heading out to see what's around the next corner?

    Join the airheads and find the local Air Marshal to find out if they get together after the virus slides away..of course riding is a great way to manage social distancing ;-)
    #17
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  18. Mobiker

    Mobiker Long timer Supporter

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    Why won't it be an issue?
    And yes, the 4 pot is a good investment. I've been totally satisfied with mine :thumb
    #18
  19. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    I think I may have an extra Harrsion 6 piston caliper for the GS on the shelf if that interests you.
    #19
  20. Bulldust

    Bulldust Bulldust

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