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Fork question

Discussion in 'Norton Commando Motorcycles (Classic)' started by geo46er, Aug 31, 2005.

  1. geo46er


    Dec 19, 2004
    I have recently had to install a center stand to help me start my bike
    (due to a disability). When I pull the bike up on the stand I hear the forks top out with a metallic clunk, other than that they seem OK. I was wondering if that is a normal characteristic of these forks or perhaps something else?
    info appreciated,
    PS. new seals a couple of years ago with a thorough cleanout
  2. kommando


    May 7, 2005
    The Clunk is normal but a design flaw, the fix is to install 2" longer damper rods.
  3. norbsa48503


    Apr 7, 2004
    There were three guys working on this kit. We talked and looked,
    And looked some more.
    First stage, strip down forks to one
    fork stanchion, one slider, one steel bushing with clip to retain,
    one high hat bush, one seal and one seal retainer assemble dry
    At this point. Check travel, got six inches plus with no dampener tube,
    valve, rod or springs.
    Ok second stage, add stock dampener tube
    with valve supporting rod, tube cap, spring, stock spacer, jam nut.
    No fork cap nuts or fluid so when you slide this back and
    forth the spring assemblies are coming in And out of the top of
    the fork stanchions tops. The travel was four and one half inches.

    Note that in this state the springs are loaded against the top of
    the dampener tube cap and are trapped by the jam nuts and the
    spacer on the other end so the Dampener valve is tight up to the cap.
    Until the bike is full assembled with the Dampener rod jam nut
    tight to the fork caps and the weight of the rider is felt the
    valve is always going To stay there up against the cap.

    The stock length of the rod Is limiting the distance the
    sliders can move. Do the same test with two inch longer rods and
    an extra set of springs For preload and you get back the
    six inches of movement. The true limit, the max to be had,
    is when the top of the steel Bushing hits the bottom of the
    high hat.
    Now you don't want to ride the bike in this state with
    the two bushes tight to one another there's just not enough
    support and the front tire Will bounce back and forth at
    stop lights. So we came up with the two inch longer modification
    for the one and one half inches of travel gain so that under
    no circumstances could the dampener valve be used
    to limit the travel for this we wanted a fluid stop and not a one and
    one half long loose fitting bushing between the two
    bushings already in the front End like the Covenant kit has.

    The springs that come with the kit are from Ford tractors and are
    the same O.D. and I.D. as Norton and Progressive springs.
    They start with a two and nine sixteenths free length and have
    have a bound length of one And nine sixteenths for one inch of travel
    . From what we know the stocks springs have one half of an inch to go with
    the slider bottomed out, that is the bottom of the stanchion hits
    the bottom of the Slider. We add one and one half of travel
    with longer rods and the extra spring adds one inch and
    the old springs had one half inch to go so the springs should
    bottom out just as the Fork stanchions do.
    Now for the fluid control
    if things were ideal one would have full movement with hydraulic
    stops at each end That is nice and slow acting right at the
    ends of travel. The best we have come up with so far
    is using ATF for fluid and leak proof brand seals it works
    on fifty bikes so far with no adjustments needed not
    that there are no Adjustments. I have one bike with stock springs
    and one with progressive springs and I have to say
    that I find the Progressive better but the stock springs work
    well too.
    On the center stands these modified bikes don't
    lift the wheels Of the ground any more but still work for me.
    The idea is to get the bike to go down from your weight
    at least one and one Half inches. Than ride around with four
    and one half potential Inches for bumps and the
    one and one half for pot holes. norbsa
  4. gokartmozart69


    Sep 10, 2005
    Re: Fork kit

    I have this kit for anyone who wants it, but only one. It is the one norbsa sold to me, which I will not use now.

    I will sell it for what I bought it for (you will save on shipping, which I will do for free).

    -David Garvin <73.Norton.Commando@gmail.com>
  5. edcommando


    Sep 18, 2005

    i just barely passed inspection this year with leaking fork seals. how hard to r and r? anybody got 2 for sale for 70 commando? thanks. ed.
  6. gokartmozart69


    Sep 10, 2005
    Just to add to my previous post, I did not install norbsa's fork kit not because it wasn't a quality product with full instructions, but rather because after a full rebuild of the fork springs, and all seals I am satisfied with the feel on the roads I commute on. I don't ride as... umm... spirited as I used to.

    Like his Boyer pickup plate upgrade kit (which I did install and has been trouble-free), this looks like a quality product. Just wanted to let everyone know I am NOT dissatisfied at all with the product, and therefore happy to pass it on to someone who will be able to enjoy the product's intended use.

    -David in Texas

    PS> to EdCommando, I got my fork seals together in a polybag from OldBritts. I believe they sell them for the Mk I Commando.

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