fork oil dirty

Discussion in 'Oil' started by 67hat34c, Mar 26, 2010.

  1. 67hat34c

    67hat34c Active Member

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    changed oil in 07 soft tail with 10k on it. Oil in forks very dirty, not milky. Left side worse than right. Dis 08 sportster at same time with 15k on it. Left side also more dirty than right.

    Is difference in fork oil apprarance due to the brake on the left side, is it a heat issue?
     
  2. bikerdad

    bikerdad Junior Member

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    I upgraded to chrome sliders with less than 2000 miles on my bike and was quite surprised at how dirty the fork oil was. I didn't notice any difference side to side, both were quite dirty. My only guess is that rubber from the seals discolors the oil quickly.
     
  3. Bud White

    Bud White Well-Known Member Retired Moderators

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    changed mine in my 08 last year at about 3500 miles and it was a dirty dirty brown
     
  4. glider

    glider Veteran Member

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    It doesn't take many miles at all for the fork oil to get dirty looking after a change. The factory fill is not the same oil as you are putting in, give it the sniff test, smells like fish.
     
  5. dlao

    dlao Member

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    just talked about this with service manager at an hd dealer and he told me "don't even worry about it until 40,000 miles"
     
  6. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    As Glider noted, don't know what the "secret sauce" is that MOCO puts in 'em, but it smells organic (fishy) and deteriorates like it too. Since the sliders/seals scrape every time the forks go up and down at an angle with every road jounce with so little oil, no surprise it gets dirty pretty fast. I would change it more often only because it is too easy to forget about it. Always changed it often on my metrics, see the HD as more stressful design due to weight and bigger included angle on the forks. JMO.
     
  7. Retrop

    Retrop Active Member

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    Seems like I read somewhere the Harley front forks are made by a Japanese company called Shidou or something similar. The article went on to point out what Glider said about using a fish oil derivitive instead of petroleum based product. All you have to do is get a whiff of that black stuff when you drain it out. Smell more like rotten fish than dinosauer guts. Enough of this fowl talk.
     
  8. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Showa, is the fork vendor...not fowl to talk about...as long as you change it out at 20,000 or sooner! :D
     
  9. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    On metric bikes that used Showa forks, the routine schedule was 20,000 miles, which worked for me from the 80's to now. Being as the HD is a heavier machine, with more fork angle (at least on my Sporty) it imposes additional stresses, so I choose to do the deed on the same schedule. Since I go over railroad tracks everyday on my way to work, I am just erring on the side of caution. Your ride, you decide of course...
     
  10. glider

    glider Veteran Member

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    Have to disagree with you here Smitty and also the MOCO too on the 50k for the fork oil change. If you inspect the oil that comes out of the forks on a bike even with 10K on the oil, you'll see what appears to be a metallic substance in the oil like a metallic flake in paint. This is the reason for changing the oil sooner than recommended at 50K. It's a wear issue IMO and I'll continue to do it every season regardless of the miles. I also feel that the replacement fork oils will do a better job than the factory fill from Showa.