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  1. #1
    Chi
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    Rock Shox Mag 21

    How much oil is needed for servicing? The manual calls for 5w light weight oil but doesn't specify how much. Anyone know?

  2. #2
    Senior Member BAC5.2's Avatar
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    Same amount you take out of the fork.
    2003 Banshee Scream. Banshee Pride!

  3. #3
    The Red Lantern Rev.Chuck's Avatar
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    <140lbs, 40-45mm 38-42psi 5wt
    140-180lbs, 35-40mm 40-45psi 5wt
    >180lbs, 30-35mm 42-50psi 8wt
    The oil is measured from the top of the leg with the slider fully compressed. Cycle it a couple of times and recheck to make sure there is no air below the damping valve. Use a little more oil to make the fork ramp up faster.
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  4. #4
    Senior Member Stubacca's Avatar
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    Chi, this link should provide you with some decent servicing tips, including oil level adjustment for the fork.

  5. #5
    Chi
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    Thanks Rev and booyah for your help. My friend is trying to fix his Mag21 that's too stiff. He thinks he may have installed a valve the wrong way the first time he changed the oil (long time ago) but he isn't sure.

  6. #6
    The Red Lantern Rev.Chuck's Avatar
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    Sometimes to get good action on mags I had to add a "valve" to the damping piston with a drill. Booyahs link may help with this.
    If your friend is a big guy using a lot of psi run the oil at 30mm and use 8 or 10wt. This will let you run a lower psi. These forks were known for seal stiction esp. at higher pressures.
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  7. #7
    Chi
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    He's a lightweight ... around 140 lbs. I think he might need to change some bushings too. Dunno.

  8. #8
    The Red Lantern Rev.Chuck's Avatar
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    He should be careful with that fork, the museum may want it back
    It sounds like he need to increase the fluid flow thru the damping plate. There is a 2.5wt oil this might quicken his fork without having to make any permanent changes.
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  9. #9
    Chi
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    ....... I'm hoping he'll register and start blurting out comments anytime now .....

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