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Plugging Timing Case Holes

Discussion in 'Norton Commando Motorcycles (Classic)' started by swooshdave, Apr 13, 2019.

  1. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I noticed that although the cases I'm going to use have the mods done to the windage and oil pickup, the holes in the timing case haven't been plugged up.

    Does it matter how you plug the holes?

    Should the holes be tapped and a short set screw with locktite be used?

    http://www.tacomascrew.com/s.nl/it.A/id.19566/.f

    I also saw mention of the plugs. Which I assume you don't thread and just drive into the holes?

    http://www.tacomascrew.com/Products/Socket-Pipe-Plugs/025-905-1_4

    I haven't found brass ones yet, I assume brass has similar expansion characteristics as the aluminum?

    And what size?
     
  2. lazyeye6

    lazyeye6 VIP MEMBER

    Joined:
    Feb 28, 2014
    I believe I read on this forum a little while back by one person that the holes were threaded and TWO short set screws installed with locktite. FWIW.
     
  3. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
  4. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Thank you. Still doesn’t say how to plug and specifically with what.

    These holes are currently not threaded.
     
  5. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    Last edited: Apr 13, 2019
  6. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I assume you don’t tap the holes which means the brass will cut the aluminum?
     
  7. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    Ever the optimist :D

    I think you would need a tap but the holes are odd sizes (around 12.5 and 9.5 mm)
    The smaller not having a lot of space around it, someone must have posted something beyond a finished picture ?
     
    Last edited: Apr 13, 2019
  8. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    One would think but I searched high and low.
     
  9. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    https://www.accessnorton.com/NortonCommando/crankcase-breather.3698/#post-34796
     
  10. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    gortnipper likes this.
  11. gortnipper

    gortnipper VIP MEMBER

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    Nov 11, 2013
    Too much of the Northwest's finest! ;)
     
  12. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    A lot of debate in that thread, one way or check valves are nothing new nor are adding reed valves, the internet simply put it out there.

    Even back in 1946 the Sunbeam S7 had a three disc and spring system in the front face of the OHC rocker cover for outward only flow.
     
  13. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I wish. More like old age and the fact that kids suck the sanity from your head.
     
    gortnipper likes this.
  14. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010

    Dave, until you ASK a question about how to do something and then discover that you (correctly) ANSWERED the same question that someone else asked 10 years ago, I wouldn't worry about it!

    Yes, I recently did exactly that on another forum (not moto related). It was pretty darned embarrassing to post a question and then get an answer within an hour saying, "Mike, take a look at YOUR post from July 12, 2009 that answers YOUR question of today! :) "
     
    baz likes this.
  15. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    You can get the right size brass hex pipe plugs from Mcmaster Carr with quick delivery.

    1/4" brass hex pipe plugs #1491N187

    1/8" brass hex pipe plugs #50785K112

    Or make aluminum plugs and hammer them in. Use a drift with a larger diameter than the hole so you won't drive them in too far.

    [​IMG]
     
    Last edited: Apr 14, 2019
  16. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Ok, I dropped my cases off with a friend in the club. He's a retired machinist and is also working on a 72 Combat engine. In fact he had his case already set up in his mill ready to cut away the windage flange when I got there today. We looked at the one engine case I have that is already cut away and discussed how much to cut and where. He has an ample selection of hardware (as any good machinist will) and has some set screws to use to plug up the timing case holes.

    Three things I need to figure out:

    1. Are steel set screws ok? Is there some reason to use brass aside from availability?
    2. Where exactly to drill the drain back hole. I know somewhere around where the oil pump is so I need to revisit all the pictures to determine an exact location.
    3. And lastly, how to make a couple reed valve bodies. I'm thinking of using the Triumph ones like @grandpaul does but make custom bodies for the back to the 72 cases. They are readily available. I think @jseng1 uses the BMW ones, which are round.
     
  17. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    Dave

    Yes I use the BMW reed valve parts. Adaptable cheap reed valves are available from Mikes XS. See return oil hole below.

    [​IMG]
     
  18. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I always thought the BMW ones were interesting. Any chance they are small enough to fit into the breather assembly on the back of the 72s?
     
  19. bill

    bill

    Joined:
    Jun 1, 2003
    DO NOT DO NOT DO NOT cut away the windage flange just relocate the oil pickup to the rear and leave the rest as is.
     
  20. gtiller

    gtiller VIP MEMBER

    Joined:
    Nov 5, 2012
    We have used metric stainless grubscrews (setscrews) to good effect on three bikes now.

    B1718567-F8DD-44C9-B92F-DD22725C55B4.jpeg

    We drive them in with JB Weld, then centre punch the thread to prevent any possibility of them even moving again.

    Sorry they’re metric - everything else on the bikes is imperial, honest guv!
     

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