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rocker shaft not "tight"

Discussion in 'Norton Commando Motorcycles (Classic)' started by Douglass Harroun, Mar 22, 2019.

  1. Douglass Harroun

    Douglass Harroun

    Joined:
    Sep 12, 2008
    One of the rocker shafts is a slip fit, rest are "heat to press" fit. Wonder if this is significant. Will it rotate? Do the tangs on the cover plates work to restain rotation well?
    I was thinking about zinc plating a few tenths of a thou on the end(s)
    Thanks
    Doug
     
  2. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
  3. eskasteve

    eskasteve VIP MEMBER

    Joined:
    Sep 24, 2012
    Colorado Norton Works used to show them on their web site. Not sure if they're still available. A quick call to Matt would be my suggestion. 970-882-7163
     
  4. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    One piece alloy plates are available from JS, NYC Norton, Holland Norton Works, and others, they’re a much better idea than the stock design which, frankly, is a bit of a botch job.

    But the RGM ones LAB showed actually use a grub screw which can tighten up hard against the rocker spindle and physically clamp it into place rather than rely on alloy tags to hold it, so are a better fix for a loose rocker IMHO.
     
    eskasteve likes this.
  5. dynodave

    dynodave

    Joined:
    May 28, 2003
    Easy to blame 1949 norton's design for (2 brain cell) ham fisted mechanics bang them in and out cold, which they probably do to their valve guides also and complain then too?
    Fire the mechanic...heat the head
     
    Hortons Norton likes this.
  6. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    That’s not my point, it’s the use of two plates and two gaskets on each shaft that I think is a botched design aspect.
     
    eskasteve likes this.
  7. Dances with Shrapnel

    Dances with Shrapnel VIP MEMBER

    Joined:
    Jul 8, 2011
    Is this a Commando head or an ATLAS head. Earlier heads had less material to support the rockers and they were prone to wallowing out. Later heads had wider aluminum bosses to receive the rocker shafts.
     
  8. Steves

    Steves

    Joined:
    Oct 16, 2016
    I have similar issue (right hand intake spindle) and to be honest while fiddly getting slots orientated and fitting the "botched" design it does not turn. As long as there is no play and the rockers are a good fit you probably do not need to worry (for now). I just spent the winter trying to sort an oil burn issue out, one of the potential culprits I looked at was this.
     
  9. napanorton

    napanorton VIP MEMBER

    Joined:
    Apr 19, 2009
  10. eskasteve

    eskasteve VIP MEMBER

    Joined:
    Sep 24, 2012
    Napanorton, nicely done! Skill and the right tools getting it done.
     
  11. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Nice job!
    I guess this could also be achieved by drilling/tapping a suitable grub screw hole in stock plates?
    Not all of us have a milling machine handy :)
     
  12. Hortons Norton

    Hortons Norton

    Joined:
    Oct 12, 2007
    Very clean design.
     
  13. kommando

    kommando

    Joined:
    May 7, 2005
    I think the stock plates would be too thin for allowing enough threads to be safe.
     
    Tornado likes this.
  14. Reggie

    Reggie

    Joined:
    Jul 24, 2006
    Pete Lovell told me quite a few years ago that with a loose rocker spindle, he places a large ball bearing over the rocker spindle hole(s) and gives an appropriately weighted tap with a hammer to spread the aluminium. I assume the amount of "welly" to give it comes with experience.
     
    Fast Eddie and Dommie Nator like this.
  15. Dommie Nator

    Dommie Nator VIP MEMBER

    Joined:
    Apr 2, 2013
    That's what he advised me too. Ball bearing is 3/4" with a flat ground on it. Don't hit it too hard The long fat nail punch pictured allows the inside spindle sockets to be addressed.
    20170723_150827.jpg If it's really worn then he advises to bush it.
     
    Last edited: Mar 24, 2019
  16. robs ss

    robs ss VIP MEMBER

    Joined:
    Aug 16, 2016
    I copied this from Jim Comstock some time ago (look for the thread if you like)
    It worked well for me.
    I think it may be superior to the ball bearing method because I believe the ball will cause only very localised deformation compared with comnoz's method.

    Cheers
    Rob

    Re: Fixes for loose rocker arm spindles?
    Postby comnoz » Thu Dec 08, 2011 6:41 am

    "A cheap and dirty trick if the outer hole is only slightly loose is to use a 1/2 inch grade eight bolt-fully threaded- along with a couple hard washers and a nut. Put it through the outer hole and torque it guten-tight. I squeezes the metal and shrinks the hole a couple thousandths. Jim"
     
  17. Dommie Nator

    Dommie Nator VIP MEMBER

    Joined:
    Apr 2, 2013
    That's ok for the outer hole, I agree.
    I was swapping a scrolled spindle for a plain one when I pressure fed the head on my Dommie and the drive side inlet spindle seemed to locate just a little too easy in the inner socket. The ball bearing method worked a treat.
     
    Last edited: Mar 25, 2019
  18. robs ss

    robs ss VIP MEMBER

    Joined:
    Aug 16, 2016
    How true - my mistake in not considering the inner one.
    I suppose the smart procedure would be to use the ball method on the inner (check for success) then use comnoz's method on the outer.
    Cheers
    Rob
     

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