R100gs Fork Oil/maintenance ???

Discussion in 'Airheads' started by Rapid Dog, Jan 10, 2007.

  1. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    Going to refresh my fork oil.
    Couple of questions. The manual sez to :

    Question #1

    "...bleed shock absorbers by compressing and releasing 5-10 times until full damping is felt...."

    Does this mean to just bounce the front end after it's all buttoned up?

    Question #2

    From one of the links I found it sez R100GSPD uses
    410cc on the Left leg and 440cc on the right.

    Is this correct?

    Question #3
    I haven't been able to find any 7.5w oil locally, only 5,7,or, 10.
    Who makes it? I see that Belray makes a 7.5w, but I thoght there may be a special sooperGSguy oil...

    your opinions are golden brothers :norton
    #1
  2. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    ceecee's
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  3. jtwind

    jtwind Wisconsin Airhead

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    I do know that the r100g s takes different levels in each fork leg. Someone can confirm if those are the correct volumes. When I can't find 7.5 weight I buy 5 and 10 and mix them in equal amounts. JT
    #3
  4. Solo Lobo

    Solo Lobo airhead or nothing

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    I'm running 15 wt, and am a svelt 175lbs.... 7.5 wt sucked IMHO...


    Then I got some Racer Tech "gold valves":D
    #4
  5. Joerg

    Joerg Long timer

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    Question #1 - Yes.

    Question #2 - Yes. The reason ist that both fork parts have different functions (compression damping is entirely controlled by the left fork, while rebound damping is controlled by the right fork), and if you do a "standard" oil change not all of it comes out.

    Question #3 - As JT said, mix it. The fork oil recommended by BMW, for the GS fork in its original state, is "Esso Komfort", which is SAE 10W. You can also use different viscosities in the two compartments; recommendations are generally SAE 7.5 (or 7.5W-15) for the left and SAE 10 (or 10W-20) for the right fork.
    #5
  6. datchew

    datchew Don't buy from Brad

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    I"m glad you asked this question R-Dog.

    Cause i'm planning this soon as well. If you replace your fork gaters, don't pay 40-something bucks apiece. Go here:

    http://www.advrider.com/forums/showpost.php?p=3823938&postcount=22

    Or go neoprene like the dirt bike people.

    BMW dealers will carry the 7.5 weight, but a thread I read long ago (and made notes from) but don't have marked said the best combination is as follows:

    L/H fork 410cc 20W
    R/H fork 440cc 15W


    Local squid bike shops carry multiple weight fork oils for me but 3/3 bmw dealers i called only carry 7.5w bmw brand fork oil.

    Jorge had something on his website about doing this as I recall. he used a ratchet strap or something to compress the forks all the way.


    Please do post if you encounter anything mysterious cause I'll need to know. Also, please tell if you end up needing some special tool like this fork drain tool in the upper left of this page:
    http://www.culayer.com/Joes_tools.htm

    Cause i have access to a welder and will just make one.

    Thx.
    #6
  7. Renegade6

    Renegade6 Been here awhile

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    I just replaced seals, oil and installed a race tech cartridge in mine a short time ago. In addition, if you are anywhere above 200 pounds go with more than 7.5 weight. For the fork caps, I just used a socket that I ground the chamfered edge off of on the top.
    #7
  8. Renegade6

    Renegade6 Been here awhile

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    I forgot to add that when I did mine the compression and rebound sides were backwards. Also, make sure you take good notes if you take them completely apart...
    #8
  9. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    I'll just be changing fluids to start.

    back in the day, we use to sit ato[ the tank to compress the forks while filling them...I assume this isn't nceessary.

    Guess I'll just go 10wt on both sides from consensus since I'm 170 bars-ass-nekkid...:puke1
    #9
  10. datchew

    datchew Don't buy from Brad

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    I'm bout 175 after a big sandwich so lemme know how it feels. Haven't bought the fork oil yet.
    #10
  11. bmwblake

    bmwblake upside down parker

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    what are the lightweights running for oil? this is on my list to do shortly.

    i'm about 150 geared up and soaking wet.
    #11
  12. cpatstone

    cpatstone N00b, obviously.

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    Just have to chime in. I used 10-wt, and it's fine for me.

    Of course, I'm about 380 lbs with my wife on my shoulders, my dog in my arms, the dog needs to pee and so do I, the wind is blowing from the southwest, and the scale reads 2 lbs when nothing's on it. :D
    #12
  13. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    ...anyone know the fork gaters size? I think I'll go neoprene if I can find some at Cycle Gear or wherever...
    #13
  14. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    So, I did the 7.5 mix in both sides...don't know what it had before.
    It seems to have more dive on braking now.
    Maybe I should bump up the viscosity on the compression side (left)?...or both sides?
    Your thoughts...
    #14
  15. hogmolly

    hogmolly Dude

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    I use 15wt on the compression side and 10wt on the rebound. It works OK for me.
    #15
  16. Stagehand

    Stagehand Imperfectionist

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    :lol3 :lol3


    :huh


    Im 15w all around, but I've got a racetech on the bench waiting for +32 temps. 175lbs, also, geared up. there was a cool thread in here a year or two ago about custom fork oil cocktails... like 12w one side, and 18.5 another... dont think I'll go that crazy, but it would be cool to try it out.
    #16
  17. moosehead

    moosehead Been here awhile

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    I use 15w and 20w L/R (or is it R/L??) with Progressives.
    But I'm 230lbs 6'
    Found 10/15w and 15/15w not right for me.
    Can start at lower weight and work your way up to heavier viscosity until you hit the right combination for your riding conditions. Takes some experimenting to find your sweet spot. Its no big deal to change fork oil in this bike.
    Good luck and happy riding
    #17
  18. wintonio

    wintonio last of the Dum Dum Daze

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    am i reading the chart in post #2 correctly that if the forks have been disassembled, add 470 cc's to both fork legs?
    #18
  19. wintonio

    wintonio last of the Dum Dum Daze

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    ok, still perhaps a dumb question, but if I have completely disassembled the forks (which I have), does the chart in post #2 say that each fork gets 470cc's of fluid?

    Thanks in advance,

    Grasshopper
    #19
  20. datchew

    datchew Don't buy from Brad

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    W - I re-read Joerg's answer to R Dogg (quoted above).

    I'd interpret it such that when Joerg says a "standard" oil change, that he means only drain and refill. In that case, the left column of post #2 would apply as it's column header is "change only."

    If you've dismantled them, that means (i hope) that you got ALL of the fluid out and thus, you'd use the volumes in the right column of post #2 titled "if disassembled."
    #20