Nightster Front Suspension

Discussion in 'Sportster Models' started by hjacobson1, Jun 28, 2009.

  1. hjacobson1

    hjacobson1 Active Member

    Just made a change that I'd let everyone know about.

    Purchased my Nightster in Feb 07 and on one of my first rides several months later, I hit a pot hole here in Milwaukee (I know that's hard to believe) that bottomed the forks so bad that it knocked the wind out of me.

    I took the bike to the dealer for the 500mi check and told them that the forks seemed to bottom out frequently, and could they look at them?

    When I picked up the bike, I was told that they had changed the oil to SE fork oil. Yes the bottoming stopped, but clearly the oil made the front too stiff.

    The stock rear suspension (Shocks) I'm sure had a production cost of about a buck for the pair as they had no damping what so ever. So it's off to look at Progressive...

    412's on the rear, and New springs for the forks...thought I was done. But the front end still seemed pretty stiff, and hard fast corners yielded some scary shakes and wallowing from the front wheel. Time to go back to the basics...

    I started by measuring the sag of the forks and was surprised to see just over 1 inch of sag. Now, when you have as little total movement on the forks as a Nightster (or Low for that matter) you really don't want to give up too much to sag.

    I then read something that Glider had said about SE fork oil and that it was 15 weight. Another thread put this oil at 20 weight. TOO HEAVY.

    After a quick trip to obtain some fork oil, (Belray 7 weight) I drained the forks, removed the top plugs and removed the spacer provided by Progressive. The space measured 3". Time for a trip to the local hardware store and I now had 24 cents worth of PVC pipe like that supplied by Progressive, but longer. Cut these pieces to 3 1/2", filled the forks with the new oil and put everything back together again.

    Measured again, and my sag now is reduced to about 1/2" and the new oil makes the forks work really well.

    A test ride of about 35 miles confirmed the results - ride improved about 300% Hard fast corners no longer yield the wallow of before and life is good!

    Made a serious good change to the bike and it did not cost HD!

    $12.95 for the fork oil and $0.24 for both spacers!

    I should mention that every procedure and measurement of oil one needs for doing this can be found in the Service Manual.

    Thanks Glider!

    Everyone ride safe.

  2. glider

    glider Veteran Member

    Glad to hear you got it ironed out Jake. It makes a big difference when you get it dialed in right for your riding style.:D

    NEWHD74FAN Experienced Member Retired Moderators

    HJ1...well done! Another satisfied rider going up from 5W to 7.5W (just a bit) and in this case raising the oil level slightly for less "sack". :bigsmiley12:

    Glider knows his stuff when he says "-- dialing it in to your riding style"...and even has suggested oil "--alchemy 101" of sorts mixing 10W with 15W to get 12.5W of the same type fork oil...if you want that viscosity. It worked for me early on when I changed fluid and lowered my Sporty as well. :D
    Last edited: Jun 29, 2009
  4. BAR1

    BAR1 Member

    Milwaukee is terrible when it comes to pot holes, trust me, I know...I live in Milwaukee County! I just try my best to avoid them because of what can in your case, but sometimes that's too hard. Thanks for posting your experience. Now I know what to do incase that happens to me. Thanks!