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Mk3 Handlebar switch gear - clean repair upgrade etc

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

  1. p400

    p400 VIP MEMBER

    Jul 14, 2014
    I have pulled the right switch gear apart and now wonder if there is any good threads on this exact Mk3 electrical components.
    Front brake master cylinder leaks look like brake fluid could add to problems as well,

    The pilot-head switch, on the upper half of this right hand switch, simply makes a circuit or not. It test with 2.0 ohms resistance when on.
    This headlight on/off makes me ask if the pilot light runs all the time the ignition is on?
    But my real concern is how far to go with inspection and cleaning ?

    View attachment 9158 20190316_193026.jpg

    Attached Files:

  2. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Nov 20, 2004
    Pilot comes ON when the ignition switch is turned to the 'Ignition and Lights' position.

    The Head-Pilot switch selects main headlamp ON or OFF at Ignition and Lights and does not turn the pilot OFF.

    It's a reasonably simple switch mechanism that will almost certainly benefit from a good clean.

    p400 likes this.
  3. p400

    p400 VIP MEMBER

    Jul 14, 2014
    I am also very disappointed with wiring diagrams i see available for this Mk3. It is as if the wiring diagrams are for one electrician to discuss with another electrician, not what is needed for trouble shooting and repairs on Mk3 electrics.
    Dashed lines representing trace wires....and which one one is trace? insane.
    Wires on these current wire diagrams are not laid out as it is on the bike, simply represented as a diagram that will fit a small space.

    WTF? Any help here ?

    I would like a 24" X 48" laid out wire diagram as accurately as possible. Color tracing as in as found. Connections/disconnects as found.
    Lucas plug connections as built.......and so forth.
  4. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Nov 20, 2004
    Dashed lines? Please explain.(Edit: OK I get it, you mean colour diagrams) Trace wires? The first letter is the main colour and the second letter is the trace, for instance, 'NU' is brown/blue, 'WY' is white/yellow.

    They are schematic diagrams but not difficult to follow.

    I will try but I'm not sure why you are having difficulties.
    Last edited: Mar 16, 2019
  5. Time Warp

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

    Dec 3, 2012
    So it should be, you do what you have to do to make that unit (or any part) 100% reliable for peace of mind.
    I think relays can be a consideration so the switch block functions (where able) are just a power source for relay activation.

    Here is a theme that seems popular.
    Hey folks, I just bolted a new (electrical thing) to my should be OK old bike not that I have checked it, the dodgy (list of 40+ year old parts) should be OK but this bum electronic ignition (or some other new part) has a miss, what a piece of crap... :D

    Generally you get back what you put in and time and elbow grease will pay off each time you pull back into your drive way with a grin on your face.

    On the same topic but off centre.
    Honda Africa Twin, switch block problems in wet climates, people taking them back to the shop........... What do I do, I check and prep those parts on my AT when I first read about it... Old bike, new bike, same same, beats walking in the rain ?
    The Buckeye Rider likes this.
  6. lazyeye6

    lazyeye6 VIP MEMBER

    Feb 28, 2014
    I'm certainly no electrical genius and I disassembled, cleaned and reassembled both of the switches on my Mk III.
    yes, it's fiddly and tiny and requires some dexterity. All yer doing is getting inside to clean up contacts. Aside
    from the mechanical aspects of the switches, it is really just plug and play unless you have wires which became
    disconnected inside the switch
    Time Warp likes this.
  7. HoveToo


    Jan 1, 2012
    Do they work? If so pack them with appropriate grease and refit. My switches were packed with normal grease when I assembled the bike from its crate in 1975. It's unsightly but the switches work fine. There are usually plenty of other areas for improvement to keep you amused.
  8. p400

    p400 VIP MEMBER

    Jul 14, 2014
    looked further into my Mk3 righthand switch.

    The upper portion is HEAD PILOT.......a simple slide switch.
    but it did show a factory crushed wire, or maybe PO maintenance.

    At first the rust colors had me concrned , but it looks like rust colored grease.

    Bought new dialectric grease "AutoZone"...Permatex product , clear gel. Coated all new clean switch with the stuff.

  9. p400

    p400 VIP MEMBER

    Jul 14, 2014
    Disassembled the bottom portion of right hand switch which contains the "off-run-off" red lever and the green start button.

    the slider for off-run-off comes out easily , and the contacts can be cleaned easily.
    i wanted to pull the two button board and the starter button, but could not budge the tiny board.

    Last edited: Mar 19, 2019
  10. lazyeye6

    lazyeye6 VIP MEMBER

    Feb 28, 2014
    Kano Kroil penetrating oil. A few drops and let it soak overnight. The board should
    work out without too much trouble. I had everything out of mine so I could clean it
    up and repaint it as the leaking master cylinder had nuked the paint. And an A/N
    MC rebuild kit stopped all leakage. I had the MC body powder coated. Epoxy spray
    paint on the switch body & cover, and then fresh white paint on the indented script (Fill and
    wipe flush). Looked like brand new when done. Overall Yes, a bit tedious and hard to do if you
    have big hands and fingers.

  11. p400

    p400 VIP MEMBER

    Jul 14, 2014
    Moved to the left side , as my turn signals were not working to the right . Left turn signal okay but timing varied on the flash.
    looked pretty dirty at first open.

  12. p400

    p400 VIP MEMBER

    Jul 14, 2014
    This left side handlebar switch simply lifted apart to allow cleaning.

    The turn lever components slide contacts were caked with old grease and were discolored.
    they cleaned up easily.



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