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Thread: Air Forks

  1. #1
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    Default Air Forks

    Seems that I remember many years ago buying a kit that tied both forks together so that you had only one valve to add air. I don't remember who made it. Does anyone know if there is a kit like this still available? TIA.
    Dale

    "The only thing necessary for the triumph of evil is for good men to do nothing." - Edmund Burke

    1982 Suzuki GS1100G
    2017 Kawasaki Versys-X 300
    1999 Kawasaki ZRX1100
    1997 Honda 250 Rebel


  2. #2
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    Some GSes had tubes that tied the forks together. One that I know of was the 1100E.

    An alternative is to replace your springs, which are probably worn out anyway, with stronger springs that will hold the weight without any additional air. Sonic Springs is one source. Progressive and Racetech are a couple more. Sonic has straight-rate springs that work very well. New springs and some fresh 10w oil changed my forks considerably.

  3. #3
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    Yeah, replacing the springs is a far better solution. Adjustable air pressure sounds like a good idea, but...it's not.
    Rich Desmond
    1980 GS1000S
    2020 Ducati Multistrada 1260S
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  4. #4
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    Default

    Quote Originally Posted by GS1100GZ View Post
    Seems that I remember many years ago buying a kit that tied both forks together so that you had only one valve to add air. I don't remember who made it. Does anyone know if there is a kit like this still available? TIA.
    If you still insist on doing it, it can be done with hardware store parts. A couple of suitable pipe(brass or some such) fittings & some PTFE hose and a Schrader valve to fill with. Easy Peasy!

    My rig in the '70s even had a small gauge included that you could watch climb when you applied the brakes!
    Last edited by slayer61; 10-29-2021 at 11:24 AM.

  5. #5
    rphillips is offline Forum Sage Past Site Supporter
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    Default

    Yep, you're right, there sure was an after mkt. kit for this, I put one on a GS1000. But been too long, don't have a clue who may have made it. Mine was pretty crude, a brass tee with a Schrader valve & 2 short lines with couplings to screw on to each existing Schrader valve.
    1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

  6. #6
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    The 83-85 GS750/700 has air forks tied together with one valve. I plugged the holes in mine and put Sonic springs in.
    Like previously said, air forks and brake activated anti-dive sound good but really don't work great.

    Mad
    83 GS750E
    2006 ZX14
    2004 KTM 450 EXC
    2001 Yamaha Big Bear

  7. #7
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    Not worth the bother, honestly.
    A few years ago I was really taken with the idea of re-instating the air forks on the GS850, because I'd fitted a set of GS1000 forks with air adjustment.
    I McGuyvered an air linkage just to see how well the idea would work, as I rapidly found that individual unlinked air forks weren't a great idea.
    After several months of battling leakage issues I gave up with the idea. They worked well, but I could never get to the stage that I only had to check the forks once a week at most, unlike the air shocks on the rear, which quite happily go for a month before losing about four psi.
    Anyway, I replaced the springs with new heavier duty progressives (can't get straight rate springs here for a sensible price) and DIYd a couple of pre-load devices on the top of the fork legs in imitation of the original GS850 adjusters.
    This combination works bloody well, never have to re-adjust them once set and it's handling well, even with the fairing and everything else on it.
    Last edited by Grimly; 10-29-2021 at 09:16 PM.
    ---- Dave
    79 GS850N - Might be a trike soon.
    80 GS850T Single HIF38 S.U. SH775, Tow bar, Pantera II. Gnarly workhorse & daily driver.
    79 XS650SE - Pragmatic Ratter - goes better than a manky old twin should.
    92 XJ900F - Fairly Stock, for now.

    Only a dog knows why a motorcyclist sticks his head out of a car window

  8. #8
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    I had thought about piecing something together but didn't know if the caps were metric or not. I also was too lazy to try and get all the pieces rounded up. I was hoping for a kit. I spoke with Progressive and they said that it would be better to go with new springs and no air.

    What weight oil is recommended for the forks? I have also heard to just use ATF. Expected load would run about 250 to 300 lbs.
    Dale

    "The only thing necessary for the triumph of evil is for good men to do nothing." - Edmund Burke

    1982 Suzuki GS1100G
    2017 Kawasaki Versys-X 300
    1999 Kawasaki ZRX1100
    1997 Honda 250 Rebel


  9. #9
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    I used an old bottle of Spectro 10W fork oil that had been kicking around for years. It seems to be working fine.
    Suzuki, back in the day, recommended a 50/50 mix of engine oil and ATF for forks.
    On my XJ, I filled them with 5w40 engine oil.
    Just about anything works, as long as it's not too far out there.
    ---- Dave
    79 GS850N - Might be a trike soon.
    80 GS850T Single HIF38 S.U. SH775, Tow bar, Pantera II. Gnarly workhorse & daily driver.
    79 XS650SE - Pragmatic Ratter - goes better than a manky old twin should.
    92 XJ900F - Fairly Stock, for now.

    Only a dog knows why a motorcyclist sticks his head out of a car window

  10. #10
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    Quote Originally Posted by GS1100GZ View Post
    ... but didn't know if the caps were metric or not.
    You're kidding, right?


    Quote Originally Posted by GS1100GZ View Post
    What weight oil is recommended for the forks? I have also heard to just use ATF. Expected load would run about 250 to 300 lbs.
    Which ATF? They are not all the same viscosity, so you may as well use a new product that has only been available for 30-40 years or so, ... FORK OIL. With proper-strength springs and the proper amount of oil, 10w oil should be fine.

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