Airhead fork oil?.

Discussion in 'Airheads' started by Sergeant Joe, Mar 25, 2010.

  1. Sergeant Joe

    Sergeant Joe Sitrep=Snafu

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    Ok, so I use ATF fluid (about 15-20 weight) in my R65ls, it's ok but somtimes I wish the front was a bit stiffer(on the bike:rofl ).
    So I was reading up in an old bike book from the 1970's that it was common practice to use motor oil of around the 20w-50 rating, so cold the oil will give the feel of a 20 weight fork oil however once it heats up it will climb to a 50 weight fork oil and will still lube all the inner bits (out of gutter please:evil ).
    Now if I do this I should get the better less spongy feel over bumps and aruond corners one would think?.

    What say you, the older set of riders from the day, should Igive it a go?.
    #1
  2. carpetburn

    carpetburn Been here awhile

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    when i put atf in the forks of my 75/6 it was terrible and hard, i find a 10wt good, what are your fork springs like? i use atf in my matchless forks but they were made in 1952
    #2
  3. jtwind

    jtwind Wisconsin Airhead

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    I've never had any issues with using the fork oil the BMW suggests. It's usually 5 or 7.5 weight. I used 10 weight in my r100gs, I think BMW suggested the 7.5 but many folks suggested 10 and it did work well.
    #3
  4. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    How many Ks on the bike?? Sounds like the springs are gone.
    #4
  5. Stagehand

    Stagehand Imperfectionist

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    I thought ATF was only about 5 or 7w. 50w in the forks? Sheesh, I thought mine were stiff as a board at 15 or 20w! That would be in the PD, and I am really working hard to crush those things.
    I would say that there is certainly something going on there... springs or something... you a big guy? :wink:
    #5
  6. Sergeant Joe

    Sergeant Joe Sitrep=Snafu

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    Good,thanks guys, I new 50w sounded a bit much:wink: .
    Now I'm thinking it may be the springs, I can test this by placing car valve springs on top of the fork springs to see if this stiffens there travel some.
    as for oil I may just stick to penrite ATF, and yes I am a bigger guy (not fat just built well, like a brick shithouse as one of my mates puts it:D ).
    #6
  7. dduelin

    dduelin Prone To Wander, Lord, I Feel It

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    Why don't you test the springs by pulling them out and measuring them for spec length? Sacked springs with car valve spring spacers are still sacked springs.

    I like BelRay 10wt.
    #7
  8. The Raven

    The Raven Banned

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    I hate to hyjack a thread, but what's suggested for my R80g/s?
    #8
  9. Stagehand

    Stagehand Imperfectionist

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    AS JT said, usually somewhere around 7.5w. Maybe a little thicker if that seems too plush.
    #9
  10. Airhead Wrangler

    Airhead Wrangler Long timer

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    If your forks are getting up to 200 degrees then you might need to figure out WHY they're doing that. That's not normal. :D
    #10