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My First Commando...

Discussion in 'Norton Commando Motorcycles (Classic)' started by Tornado, Jan 12, 2018.

  1. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Needle and needle jet are as I recieved bike back in January...likely original...but odo shows 8300 miles and that seems a legitimate mileage for the overall bike condition.
    I have not tweaked any carb screws since getting it back from shop last week. They spent quite a bit of time tweaking it and I didn't want to stray from those settings after spending $300 for their "pro" efforts.

    Prior to shop work, I had the pilot screw at recommended 1 1/2 turn out.. and fiddled it in/out upto 3/4 turns to try to settle idle. Never got it nice and low like the shop did, but note it had a stumble even then, before shop touched it.
     
  2. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    $300 !!!! Take it back to them and get it done properly
     
  3. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Shop rates here start about $100 per hour and they had the bike over 3 hrs. He spent a while working the carb over and got the pilot circuit cleaned up much better than I was able to...hence the way better idling....and he set the dynamic timing (my original reason for taking it in), changed the plugs. He said it really should just get a new carb...actually said TWO new carbs....and I'm not ready to go there yet. They are about to close the shop for good...owner retiring.
     
  4. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    Basically if you do have a go yourself and you may find that just another quarter of a turn out in the pilot screw will cure it
    If not try a new needle jet
    If not that then try a larger slide cuttaway ,if you have a spare one in the other carburetor try filing 1/2mm off of it ,also you can try lowering the needle one notch ,
    If none of this works it's possible (but doubtful) a PO has opened up the pilot jet bush you should not need to be more than 3 turns from fully seated on the pilot screw, but if you are then the bush has probably been opened up
    I assume your air filter isn't clogged up? Hope you get it sorted
     
  5. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    My next question was going to be "did the shop adjust the carburetor at the engines working temperature" but I guess they must have done if they have been around a long time
     
    Last edited: May 29, 2018
  6. oldmikew

    oldmikew

    Joined:
    Jul 25, 2015
    I would check to make sure that the main jet is not loose ... Order yourself a floatbowl gasket , a needle jet and a needle clip and a float needle . Look on Amal website for sectioned diagram . Its not difficult to do your self. Oh and one last point try backing off the throttle slide screw if mixture screw has no impact on tick over .. Its really not difficult to do this stuff and we all start somewhere. good luck and enjoy
     
  7. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    It’s possible the shop put too much emphasis on ‘perfect slow idle’.

    A lot of the old bike boys here put a lot of effort into that. It’s become the older riders equivalent of pub bragging rights to have the slowest, metronome type idle they can.

    I recently set up the carbs on my T120 and found that when I got that perfect idle, I also had an off idle stutter. I had to enchrichen it a little on the air screw and sacrifice some the of that pub bragging idle, it went lumpy, and I therefore I had to speed, in order it up to get better low end throttle control.

    We should also remember that a too low idle is bad for cam oiling ...
     
  8. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    Well speak of the devil , the right main jet holder was nearly out, just hanging on by a couple of threads. Put new needle jets in anyway and it runs like it should.

    Glen
     
    Tornado likes this.
  9. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Good catch Glen.
    While awaiting new needle and [HASHTAG]#106[/HASHTAG] jet, I'm doing a valve clearance check and now adjustment on my T100 Bonneville. Man, the Norton beats this task easily...30 min vs 5+ hrs on the Bonne. Measuring clearance is ok, but then if any out of tolerance the cams need to come off so you can determine current shim thickness, then run to a shop to buy correct new shims. I got my cams off too late in day to get to shim shop...so first thing tomorrow.
    Old ways way easier!
     
  10. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Update:
    New. Needle and 106 jet installed. LED headlight BPF and Pilot light installed.
    Took her out for test run after tweaking idle a bit. Seems to be running about as good as before but stumble off idle happened once...a bit more tweaking and seemed to be cured. Went up the mountain for a 30 mile run...going great at speed.bit of popping when letting off throttle still in gear around 3 k rpm...normal?

    Here she is top of mountain in the fog:
    IMG_20180621_135725.jpg
     
    cliffa likes this.

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