PWK carburetors for Norton MK3

Discussion in 'Norton Commando Classic Motorcycles' started by nortonisthebest, Apr 13, 2018.

  1. nortonisthebest

    nortonisthebest

    Joined:
    Aug 1, 2014
    OK, I think this might be why I'm not getting the bike to idle, the hole must be plugged!
    I did soak the carburetor in carb cleaner for one hour yesterday and it looks new.
    I ran some fine wire, about an inch long, through it and shot some carburetor cleaner in the hole. However I can't see where the carburetor cleaner is coming out anywhere? Where is it going? I wonder if it still plugged? I would hate to put it back on the bike and still have the same problem without knowing for sure.
    Thanks again for all your responses.
     
  2. Bob Z.

    Bob Z.

    Joined:
    Mar 30, 2012
    Suggest that you remove the idle air screw and float bowl.
    Then look inside that idle air screw hole and confirm that the brass pilot jet (with the .016 hole) is in place.
    Then stick the carb cleaner spray tube into the idle air screw hole and place your finger over the two holes on the carb opening mouth end.
    Spray the carb cleaner and you should see the cleaner spray through that small threaded hole (original pilot jet hole).
    Put a clean dish to catch the spray and see if any debris is ejected.
     
  3. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    You absolutely have to remove the pilot air adjusting screw and poke a 16thou wire through the pilot jet bush
    Carb cleaner will not do the job on its own,
    Maybe consider getting the single carb mikuni kit
    This has been much discussed lately ,if you don't want to rev the bike really high or go much above 90 mph then the single 34 mikuni is hard to beat cheers
     
  4. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    The jets probably weren't missing. As Bob Z says, Amal moved its location and changed it from a screw-in jet to a pressed-in 'bush' on 4-stroke carbs.



    Except for very early 4-stroke and 2-stroke Amal Mk1s the pilot jet is directly opposite the pilot air screw and can be seen in the RH picture.

    http://amalcarb.co.uk/rebuilding-mark-1-concentric-carburetter


    [​IMG]


    http://www.jba.bc.ca/Bushmans Carb Tuning.html

    [​IMG]

    [​IMG]
     
    Last edited: Apr 16, 2018
  5. nortonisthebest

    nortonisthebest

    Joined:
    Aug 1, 2014
    Guess what, it worked!!!! I am now getting carb cleaner through the small threaded pilot jet hole on both carburetors. The .016 wire worked great. I could feel it brake through I then used cleaner and compressed air to clean it. The pictures really helped to see how I had to do it.

    Thank you all for all your help, you saved my bacon! Wow
     
  6. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    Ok brilliant well done,
    Those pilot bushes are tricky
     
  7. Steves

    Steves

    Joined:
    Oct 16, 2016
    Let us know the result when bike is back running
     
  8. nortonisthebest

    nortonisthebest

    Joined:
    Aug 1, 2014
    Hello,
    I just got back from a 30 mile test ride and it ran great. Very smooth and responsive with it idling as it should. I just need to put some miles on it and brake it in.
    Don't you just love it when things come together.
    Thanks again for all your help. You have saved me a lot of dollars and headache.

    Paul
     
  9. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    That's the great thing about this site sharing knowledge and helping others
    Great news mate
     

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