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Oil Tank Mount Broke

Discussion in 'Norton Commando Motorcycles (Classic)' started by swooshdave, Jul 1, 2019.

  1. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    [​IMG]

    So I had used the bigger exhaust mounts as I had read that they held up better. They definitely didn't allow it to move much. I think the strain was too much and the rear tab broke.

    [​IMG]

    I didn't really notice because I have velcroed the tank to the battery box. This is industrial velcro, not the stuff on your shoes. It's VERY strong and tenacious.

    I also didn't use a bottom mount at all, it just hung from the bigger upper mounts and the velcro. There's no sign of the bottom of the tank hitting anything.

    Options:
    Get the tab welded back on.
    Use the smaller oil tank rubber mounts.
    Use a thick silicone pad under the tank.
    Just use the front rubber mount and velcro.

    I actually hold the battery (smaller form factor) in with velcro. It does not move at all. Apparently the velcro from the oil tank does not transfer the heat from the oil tank to the battery box to the battery. At least if it did I'd expect cooked batteries. So far I think I've only used one battery in however long, 7-8 years?
     
    nortriubuell likes this.
  2. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    I use Velcro in those applications too swoosh!

    I also don’t use the bottom mount, mine was fixed / modded by cNw that way.

    I’d Suggest get the bracket fixed and using softer bobbins for the two top mounts, and then inserting some foam (or similar) under the tank to also help take the weight / strain.
     
    nortriubuell likes this.
  3. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    +1 on what FE said. I had run for 20 years without a bottom bolt and no support there and went thru a few oil tank bobbins. That was worth not having to deal with the bottom bolt, and before CNW was smarter than I am.

    Now I support the tank with a petrol tank pad and still use the proper mounting bobbins.
     
  4. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Yes, the best way is the cNW method - remove the bottom boss and have the tank resting firmly on the pad so that all the weight/strain is taken up by the entire bottom of the tank. The upper mounts basically just keep the tank aligned. Norton knew that at the beginning - support the bottom. They just didn't do it very well with that little boss taking all the strain instead of the entire bottom. :(
     
  5. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    I just cut a hole in the center of the pad, so the bottom of the tank rests on the pad without having to modify it.
     
  6. kommando

    kommando

    Joined:
    May 7, 2005
    I repaired 2 tanks that leaked from the bottom mount by grinding the mount off and then having a plate welded on top. I now use larger top mounts and the bottom of the tank sits on a polyurethane pad and that has lasted years. I can only guess that in your case there was still a strain on the top mount and playing around with the thickness of the bottom pad will help.
     
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  7. maylar

    maylar VIP MEMBER

    Joined:
    May 13, 2007
    Mine has broken numerous times. Welded, reinforced, welded again. Got a used tank from my buddy and that one broke too. I've always used the factory rubber mounts and they've been replaced a few times. Never thought about Velcro - that's a good idea (I have some industrial grade stuff too). Finally bit the bullet and my cNw mod'ed tank will be installed this weekend.
     
  8. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I think the strain from the larger exhaust mounts put too much stress on the bracket.
     
  9. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    Yup softer rubbers up top , just a soft rubber pad for bottom and against battery side , Velcro holds my battery as well , thought I was only person daft enough to think of and use it , learn something each day , eh ....
     
  10. rvich

    rvich VIP MEMBER

    Joined:
    Jul 25, 2009
    I've been wondering about using springs in tension. It hasn't moved much from idea to concept yet.
     
  11. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    You'd have to have just the right springs. And they don't have any dampening. Rubber both moves and dampens.
     
  12. rvich

    rvich VIP MEMBER

    Joined:
    Jul 25, 2009
    Finding the right springs are a problem for sure. And figuring out how to mount them. But as an example, my washing machine tub is mounted by springs in tension to keep it from banging when it goes into spin cycle. And its forty years old and still going. I'll step up my research and development and see what I can come up with.
     
  13. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    I suspect hardy springs could very well work , just a lot of time and brain work compared to trimming some soft rubber and placing it ...
     
  14. cNw

    cNw VIP MEMBER

    Joined:
    Apr 16, 2009
    Part of what makes the cNw oil tank mod work is that the rear tank mount is changed and far stronger than the original. I also use a rubber mount that is soft enough to allow movement since one that is to rigid (like the HD type) will transfer the load right into the mount itself. A rigid mounted tank will eventually break somewhere

    Matt
     
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  15. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
  16. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    You can also use the extra pads that come with a Shorai battery that are for bulking it out when replacing a full sized battery.
     
  17. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    If you have a Shorai battery. What are the pads made from?
     
  18. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    Closed cell foam, adhesive backed. Not quite as stiff as the petrol tank pads from AN, but I have used them for a number of things and they work fine. And the batteries come with a wad of the stuff of varying thicknesses.

    You can see the stuff here -

     
  19. norton73

    norton73

    Joined:
    Dec 11, 2008
  20. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    My uppers gave way long ago and replacement proved to push my patience past the point of no return the times I attempted to do right by them, so I settled on some padding I'd come across which has done me more than well. It is a dense whitish semi-tough foam. Hard to describe & thought it was foolish at the time, but it holds up & resists heat and oil. It came as packing on heavy items. After trimming to fit & securing the tank hold fast with adequate give, also works well keeping the battery from damage.
    Couldn't keep my $.02 out when the padding came up because it works great if done right with none the wiser and no headaches.
     

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