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Zener diode ground

Discussion in 'Norton Commando Motorcycles (Classic)' started by DogT, Aug 29, 2010.

  1. DogT

    DogT VIP MEMBER

    Joined:
    Jan 20, 2009
    Where does the ground (red wire, positive ground) attach near the RH Z-plate zener on the early 69/70 models. I can see the spade lug (brown white/white brown) goes to the zener, but where does the red wire with the round lug go, I tried under the zener, but that didn't seem to work. Maybe under the passenger foot rest? My notes only say ground??

    Dave
    69S
     
  2. Jeandr

    Jeandr

    Joined:
    Jan 22, 2008
    Doesn't it go directly on the stud of the zener :?:

    (you could just put it anywhere that is a good ground)

    Jean
     
  3. MarshalNorton

    MarshalNorton

    Joined:
    Jan 30, 2009
    Dave,
    Z plate has 1 bolt going into it from outside of plate the other 2 are studs on the Z plate.
    The bolt and washer go through Z plate then the eyelet w/ red wire goes on bolt.
    I then added an additional washer so I didn't mash the brass eyelet with the nut.
    A drop of old blue locktite and screwed the nut down snug only.
    If you didn't see it for yourself you would never believe it goes there.
    The only reference to its proper location has been an old Haynes manual and an excellent Clymer manual which
    I refer to most often.
    Its kinda goofy there but that is the factory location.
    Marshal
     
  4. CanukNortonNut

    CanukNortonNut

    Joined:
    Aug 8, 2005
    Hi MarshalNorton
    I Know 72-74 Nortons had the Red eyelet bolted to the rear Foot peg assembly with a course bolt and nut on the inboard side of the Z plate. I think the reason the factory did this is to keep it just close enough to the zener so as to make the Z plate act as a better heat sink. Me thinks. :wink:
    CNN
     
  5. DogT

    DogT VIP MEMBER

    Joined:
    Jan 20, 2009
    I tried it under the zener, but the eyelet was larger than the 1/4" stud on the zener and it just didn't seem right. It fits nicely on the rearmost 5/16" UNC footrest bolt if I make it longer and put a washer and nylock on it. I replaced the studs on the footrests with SS bolts. I did the same with the front forks where I could replace studs with bolts for the bridge. Don't know why Norton used all those studs and nuts, maybe cheaper?

    Dave
    69S
     
  6. maylar

    maylar VIP MEMBER

    Joined:
    May 13, 2007
    As Marshall noted, the rear most fastener on the right side footrest is a bolt and the other 2 are studs. The bolt is long enough to take the ground lug, a flat and lock washer plus nut on the back side of the z-plate.

    Don't put the ground lug under the zener - you want intimate contact between the zener and z-plate for heat sinking. That's why the plate is milled with a flat recess back there. In fact, a bit of silicone heatsink compound between the zener and plate is recommended.
     
  7. DogT

    DogT VIP MEMBER

    Joined:
    Jan 20, 2009
    Yes, I have some GE silicone thermal grease I put on the zener. Same stuff I used on the isolastic donuts. I even put a brass nut on it to match the stud.

    Dave
    69S
     

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