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primary chain hydraulic tensioner assembly doesnt make sense

Discussion in 'Norton Commando Motorcycles (Classic)' started by p400, May 16, 2019.

  1. Esmerela

    Esmerela VIP MEMBER

    Joined:
    Jan 9, 2017
    Jimbo

    You don't really need to try and go with fully primed wet assembly, when the steel plate is fitted to the front of the tensioner if creates a well between the tensioner body and the back of the plate hence the gasket. You can fill this with oil and prime up the assembly by squeezing the slipper plungers, there are vent holes in the plungers to help purge some of the air.
    If the bike has stood for a long time, with the aid of a syringe you can fill the well through case filler hole and prime by lifting and depressing the chain before stating.
     
    Last edited: May 17, 2019
  2. Esmerela

    Esmerela VIP MEMBER

    Joined:
    Jan 9, 2017
    Hi Lab

    Looks like that chain or one of its predecessors has been lunching on the inner primary cover at some point.
     
  3. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Yes, it must have been a predecessor!
     
  4. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    I looked at my spares, one plastic piece looked to have some kind of glue on it and the knob end seemed to be forced into the spring. The only spring I had was kind bent out of shape after messing with it a while I got it to go into the plunger bore. Installed both ways the spring and plastic piece inserted into the body could be compressed flush and pushed all the way in. When assembled correctly ,the knob on the plastic piece away from the bottom of the plunger it was obviously stiffer but not too bad.

    DSC09961.JPG DSC09955.JPG DSC09956.JPG DSC09957.JPG DSC09958.JPG
     
    p400 likes this.
  5. BritTwit

    BritTwit VIP MEMBER

    Joined:
    Aug 25, 2009
    It almost appears that the spring end may have over-worked the plastic cap and machined/cut the plastic cap material enough to allow the spring to slip over the cap region and slide down the plastic shaft.

    [​IMG]
     
    p400 likes this.
  6. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    Could have, it almost looked like it was melted. However that messed up piece probably just confuses the real issue, and we should probably disregard it.
     
  7. BritTwit

    BritTwit VIP MEMBER

    Joined:
    Aug 25, 2009
    The MK3 manual diagram doesn't help much either, except that there doesn't appear to be a cap end of the plastic rod facing toward the tensioner.
    This may imply that the cap end should face the spring.

    [​IMG]Hosted on Fotki
     
  8. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    in the shop just now,
    coil bound length of the spring is 1.00"
    depth of plunger tube is 1.670"
    length of plastic piston is about 1.00"

    What is the depth of the bores in the tensioner alloy body?
    I don't have one out right now.

    don't tell me this is wrong way, it is just for measurement.


    20190517_tensionerAssembly22.jpg 20190517_tensionerAssembly33.jpg
     
    Last edited: May 17, 2019
  9. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    What is the depth of the bores in the tensioner alloy body?
    its 13/16", your assembly will not fit flush( the bottom of the tensioner alloy body hole is tapered, and would show a little more depth if measured from the center) However your new white colored plastic spacer seems longer then my old unmangled discolored one.

    correction it should be 1 13/16"
     
    Last edited: May 18, 2019
  10. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    My tensioner springs = 0.83" Edit: And, spring wire diameter is 0.031".


    The two plungers of mine are slightly different:

    = Internal parallel sections 1.86"/1.856"

    External tubes 1.8"/1.78"

    The compressed spring does not become coil-bound until fully inside the plunger tube with the nylon plug as AN's drawing.

    = Same.


    = 1.81"

    [​IMG]

    [​IMG]



    1.13/16"? (1.8125")
     
    Last edited: May 18, 2019
  11. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    1.13/16"? (1.8125")[/QUOTE]

    yes 1 13/16" that was a oops
     
  12. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    p400 said:
    depth of plunger tube is 1.670"
    Click to expand...
    The two plungers of mine are slightly different:

    = Internal parallel sections 1.86"/1.856"

    p400, you might have something in the bottom of the plunger tubes
     
  13. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    It is quite obvious that we do not understand this primary chain tensioner, at all. or the replacement parts available for this device.
    I am not meaning to confuse this issue. 2019-1975 = 44
    Here are more pictorial data.
    I am beginning to doubt the replacement parts.

    My spring wire is 0.032" diameter wire, 29 coil count, 4" free length, 0.959 compressed coil bound

    20190518_CompressedSpring1.jpg

    20190518_PistonLength1.jpg
    This picture is not well aligned, measuring outside edge diameter of piston to tail.

    20190518_PistonVsPlungerHole1.jpg

    20190518_PlungerTubeDepth1.jpg
    this is the length of the plunger bore at the "shorter" outside edge.
    this inside bore has a dished end that is slightly deeper 1.722"-1.724"

    20190518_PlungerTubeLength1.jpg

    plunger tube length externally
     
    Last edited: May 18, 2019
    dynodave likes this.
  14. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004

    0.032" is 21 SWG and therefore, a standard wire size although mine seem closer to 0.031".
    From my photo mine appear to have just under 26 turns.


    My 'RENOLD ENGLAND' plunger tubes are certainly longer internally so along with the extra spring coils it seems the replacement parts are the problem.
     
    dynodave likes this.
  15. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    I was able to purchase what appears to be an NOS plunger with a 26 coil count.
    not arrived yet.

    PlungerEbay1.jpg
     
  16. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    FYI, I had the plastic piece with the button in the bottom of the plunger, the wrong way , it worked fine( had some slap maybe it will be better when I assemble it the "right" way).
     
    gtiller likes this.
  17. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    my springs are .843" compressed


    mine are 1.890"
     
    Last edited by a moderator: May 21, 2019
  18. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    received an NOS plunger kit, on the left -
    spring is different
    white plastic piston is different
    steel/rubber plunger is different

    Andover used pieces on right


    20190522_190456.jpg
     
    Last edited: May 23, 2019
  19. Madnorton

    Madnorton VIP MEMBER

    Joined:
    Jun 9, 2008
    What is the free length of the spring on the left?
     
  20. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    3.2" is the length of the NOS spring
    26 coils, 0.032" wire

    20190523_172051.jpg
     

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