pre oif a65 swingarm options, swaps, extending etc info..

Discussion in 'BSA' started by 84ok, Mar 15, 2018.

  1. 84ok


    Aug 10, 2014
    covered front end options for this model/frame in another thread so...

    tons of info out there for back end options for other makes/models, just gonna ad pertinent info here as i run across it,

    turns out, goes back ..some time in this info from ~ 66 (click on pix to enlarge),

    from an ebay ad google - BSA C15 B40 B44 Victor trials vmx vintage motocross mx AHRMA swingarm extenders
    Last edited: Mar 15, 2018
  2. grandpaul

    grandpaul VIP MEMBER

    Jan 15, 2008
    If you have a cut-off wheel, torch, welder, grinder, lathe, mill, and stock materials, you can make ANYTHING fit ANYTHING.

    There is a nice, simple swingarm bracing scheme for classic Britbikes also.

    These welds were NOT mine, I inherited it; I beefed up the birdpoop stuff to where it actually adds strength...

  3. kommando


    May 7, 2005
    I cut 2 C15 swing arms so the 4 cuts when the halves were swapped gave 1" longer arms on one swingarm plus some bits which could be used to make a short one, but are in the scrap bin. Into the longer arm joints I inserted some short sections of tube with OD matching ID or the swingarm tubes and left 1/4" gaps for a welder to fill and joint the halves up. Dressed the weld and ended up with an extended C15 swingarm.
  4. 84ok


    Aug 10, 2014
    looks like there were 3 diff swingarms for pre oif a65, for years 62-4, 65-8, 69-70, no details yet other than mounting part(s) diffs for 65-8 vs 69-70

    i'm gonna focus on 67 cos thats what i have

    i don't have many of those skills, or experience, in making a change, first thing most folks look for/at is what options & info is out there, having access to info allows easier decision making to then move forward with,

    if you google xs650 swingarm swap, there is tons of available info, along with other makes & models vs practically diddly for a65,

    ran across some stuff tho, an oif a65 deal

    high end

    vs home brew

    i'm looking for all dimensions like these
    xs650 - Pivot Tube:
    ID - 16.02 mm - (0.631")
    OD - 21.95 mm - (0.864")

    norton mk3 spindle OD
    Swingarm Pivot Spindle, MK3, .8745" O.D.

    a65 pre 69 "Spindle Diameter: 5/8" (16mm)"
    5/8" = 0.625

    some of the options for xs650
    key point, the SR500 and XS650 swingarms have the same pivot dimensions

    other stuff

    diy jig

    it would be sweet, if a xs650 swingarm swap was doable via some cheap easy mod,

    pretty sure the yam tx750 swingarm, bit bigger, beefier & longer is a direct bolt in for the 650 frame

    some mods with a kz1100 conversion,
    luv this guy, sez in the thread "This is the first engine I've ever worked on, so any tips would be very appreciated" lol
    Last edited: Mar 18, 2018

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