The 101 Association, Inc.
For the preservation and enjoyment of 1928 to 1931 Indian Scout Motocycles
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Leaf spring setup. Words of wisdom from the late Jerry Greer

  • 23 Jan 2021 1:07 AM
    Message # 9954635

    [Quote]Jerry Greer:

    "The most common fault in leaf spring setup is found at the rocker pivot pin to fork leg not being dead-on center aligned with each other and/or the holes on lower fork legs are wallowed out or one or both "pads" surrounding the holes are very worn from the rocker pins left loose for years.

    When you tighten the rocker pivot pin it's at a crazy angle to the fork spring eye stud, causing bind when stroked through the spring stroke arc.

    Easiest way to determine bind is to tighten everything in the rocker assembly.

    Complete front wheel/axle assembly must be installed tight.

    Fork link rods must be installed properly to the rockers.

    With the wheel at its working rebound "droop" position, try to install and tighten the spring eye stud to both fork link rods. If everything is correct, the stud should easily shoulder up tight to the fork link rods without distorting ANYTHING.

    Remove the stud and repeat test with front wheel at its "full bump" position and results have to be the same for complete freedom of the linkage to move and not impart any torsion or bending resistance to the action of the leaf spring pack doing its job.

    In short, all the pieces, together, need to be a nearly perfect inflexible rectangle, moving freely through all the perfectly parallel bushings and mating pins.

    I didn't explain it simply but the concept is dead simple.

    The rub is that fork leg bottom rocker pin holes are always f'd up quite badly and have to be fixed first.

    Except for only being able to process small bumps, when restored properly, the Indian leaf spring fork is heads and shoulders superior in handling to the girder and telescopic forks as designed.


    Last modified: 23 Jan 2021 1:08 AM | Carl-Erik Renquist
  • 23 Jan 2021 11:34 AM
    Reply # 9969698 on 9954635

    Thanks Carl-Erik!  Wonder what the best way is to test at the "full bump" position?

    Last modified: 23 Jan 2021 11:36 AM | Harry Roberts
  • 24 Jan 2021 11:18 AM
    Reply # 10005889 on 9954635
    Tim Raindle (Administrator)

    Harry, here is a prime example of a running restored bike that had front end issues. One of the rockers was slightly bent. Same effect can be had by worn bolt holes in fork, worn inner face of fork leg mounts where the bolt sits, a twisted spring, or most commonly mismatched hangers. These are cast malleable, and easily bent. It only takes a very small bend to misalign mounting holes at the top or bottom and cause the whole linkage to bind .

    2 files
  • 30 Jan 2021 3:22 PM
    Reply # 10048920 on 9954635

    Hi Tim,

    In the fixture shown in your message, what is the width of the tube on the right that is acting as the rockers?

    Dave

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