Airhead GS Fork Seal Q

Discussion in 'Airheads' started by NHGS, Nov 1, 2004.

  1. NHGS

    NHGS Granite Scrambler

    Joined:
    Nov 20, 2002
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    Central VT + Manchester, NH
    Halfway through a recent 700 mi. trip, I noticed a few oily spatters on the left jug and crashbar of my 94 GS. A quick inspection revealed that the fluid had come from the drain hole of the left fork boot. The amount was small and there was no apparent difference in handling, so I wiped up the spatters and kept an eye on it during the ride home. If it had been leaking on the right, I would have had serious concerns about continuing on, since I would be afraid of fluid interfering with the front brakes. But the amount had been small and seemed contained to the left, so for the rest of the ride, during daylight hours, I kept a sharp eye on the area and saw no evidence of fluid leaking. When I got home, after riding about an hour through the dark and 35 degree temps I saw a significant amount of fluid on the crashbar again. Needless to say, now that I'm home I will be replacing the fork seals.

    My question is, if the fork seal had failed completely 350 mi from home, on a Sunday afternoon, what would be the best course of action? Is there a roadside repair that can be done? Can one/should one limp home? What are the consequences or potential related damage?
    #1
  2. Malindi

    Malindi Zen Adventurer

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    You can ride home. Thousands of miles have been covered in the desert with shot seals.
    #2
  3. Mr Head

    Mr Head PowerPoint ADV

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    You won't kill anything riding that short distance. However, I would drain the remaining oil and wipe all of it off the front, you do not want that stuff on the brakes, (trust me I've checked this out personally on an airhead GS, it wasn't nearly as much fun as it sounds). The forks will bottom easier and there won't be any damping, but you will still be able to ride.

    Make sure the little 10mm nut at the bottom of the fork is tight, don'y break it off, since that is what holds the fork slider on the leg.

    The fork gators should minimize dirt getting in the fork and making a mess of the leg or slider. I'd just drain the oil and go about my business. Fix it when I got the parts. Installation of new seals is the tricky part. Too many people screw it up and fail the seal before they even get the thing together, or mess up the fork slider removing the old seal.
    #3
  4. Gringo

    Gringo simple by nature

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    The left seal on my bike developed a leak pounding through the WV woods trying to keep up with Steve, Poonie and Jabba in September; discovered it a couple days later on the Jersey Turnpike headed home. I didn't even think to drain it since it didn't seem to be getting anywhere near the brake - it all blew straight backward onto my leg and the left jug - but draining is probably good advice if the brake is at risk. I didn't notice a tremendous difference in handling with the oil low, maybe a bit more brake dive, but in my case it was the 'rebound side' of the fork...

    But what do you mean by 'if it had failed completely'? Having had mine apart recently, I can't imagine how it could fail so completely that it's unrideable over a couple hundred mile run homeward. Maybe on a much longer ride it could get catastrophically worse. But there is no way that the whole seal could get spat out past the nasty retainer circlip (bitch to get out), and in my case although it was pissing oil like crazy, when I had it apart I really couldn't see where it had failed - there was no split or anything real obvious like that, oil was just getting past the seal along the tube is all. Mine seemed to be get gradually worse over the 600+ mile ride home, but maybe it just got blown around more and more. It made a mess, but I checked the fork tube carefully and no scratches or anything. New seal holding, bone dry after several hundred miles now, so I doubt there was any damage from my abuses.
    #4
  5. NHGS

    NHGS Granite Scrambler

    Joined:
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    Central VT + Manchester, NH
    Good question. I guess 'failed completely' would mean getting to the point where the bike handled erratically or felt unsafe enough to continue on. (I had the stock rear shock fail last year fully loaded and it was not a fun ride home, even though it was only 20 miles.) Since it never felt that way, I got to wondering whether the leak could eventually result in a crippling breakdown and what I would/could do if it got to that point.

    Thanks everyone for the replies!
    #5
  6. Gringo

    Gringo simple by nature

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    yeah, I remember that rear shock of yours looking a little bloody at Cro-Mag last year.

    good luck! Be careful getting that circlip out - it's practically invisible and has nothing more than one beveled edge to pry it out with - can't imagine what special tool, if any, BMW has for this job. Tried my patience more than just about anything I've ever done on this bike.
    #6
  7. Jabba

    Jabba "HOLD THE LIGHT!!!"

    Joined:
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    I blew three fork seals on my airhead in two years- and never had a rideability issue that I couldn't deal with. The bike would pogo more and dive under braking- but never to the point of feeling dangerous. I believe the primary function of the oil is for damping purposes- so if you lose the oil you lose your damping- doesn't do anything to the spring tension per se- so you still have "suspension" just not as controlled and "settled" as when the oil level is correct. One thing I learned going through those seals (logging roads up in PBurg can be rough as hell!!!) is to use heavier oil if you want more preload up front- not a higher quantity of oil. There are two philosophies on this- that you can achieve more pre-load with either more oil, or the same level of oil with a higher viscosity. I had FAR better results and stopped the seal failure issues when I stopped increasing the volume and stuck to the higher viscosity method. FWIW
    #7
  8. Caribou Aqua Buddha

    Caribou Aqua Buddha Long timer

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    When I worked in the industry years back it was common to have a bike come in with no oil in the forks, because the seals had been blown for years. Oddly sometimes the customer did not even realize, and sometimes that was not even the reason the bike was brought in. :huh
    #8
  9. deerslayR

    deerslayR Spodely Adventurer

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    Hi YFF,
    I have made a temporary fix on my GS with a piece of film negative. Remember film cameras :rofl ?
    You work it in between the tube and the seal and force the offending "chunk
    of dirt" away from the seal lip. You said that you saw no tear or any other
    indication of a failure? You may have replaced a seal which might have been saved. Just my 2 cents.
    Are you coming south for the "Turkey Ride" this month? Would love to show you my playground. We ride until the snow's too deep to see the stumps.

    RF/TC

    deerslayR
    #9