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Bike won’t start

Discussion in 'Norton Commando Motorcycles (Classic)' started by auldblue, Jul 10, 2019.

  1. auldblue

    auldblue VIP MEMBER

    Joined:
    Nov 20, 2012
    The 750 has been off the road for a new box and it started up and ran fine then gave a cough cut out and refused to start. Changed the plugs checked for a spark it was fine , turned it over checked the EI rotor, all good still no start, it tickled fine but not even like firing ,put a drop of petrol in the plug holes and it started up ran and stopped. Had the carbs to bits , bowls were full of fuel and pilots were clear, what am I missing here?
     
  2. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    Probably plugged idle circuit from being parked with fuel in the bowls.
     
    MexicoMike likes this.
  3. acadian

    acadian VIP MEMBER

    Joined:
    Mar 5, 2010
    that, or you need a new johnson rod...

    sorry, couldn't resist
     
  4. auldblue

    auldblue VIP MEMBER

    Joined:
    Nov 20, 2012
    I’ve got her running but it takes a handful and it fires and runs with no strange noises.
     
  5. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
    Have you tried cleaning up the fuse contacts , the kill switch , the ground(s) ?
     
  6. auldblue

    auldblue VIP MEMBER

    Joined:
    Nov 20, 2012
    Yep I have , I did notice my ignition light go out and I may have to replace the switch and or barrel but I’ll go through the wires and contacts again for peace o’ mind.
     
    Torontonian likes this.
  7. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    If it runs ‘with a handful’ it does seem to support the idea of the pilots being blocked (fuel circuit blocked but air circuit open perhaps?) as, by giving it a handful, it’s no longer trying to run on the pilot circuit.
     
  8. auldblue

    auldblue VIP MEMBER

    Joined:
    Nov 20, 2012
    Yup , yer right basically over riding the pilot circuit, I'll have the carbs off again Nigel as I don't think I did a proper job the first time.
     
  9. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
    A fine guitar string or Banjo works well with some cleaner spray.
     
    jbruney likes this.
  10. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Jimmy it’s very easy to blow the carb pilot circuit out with air and think they’re free, but actually all you’re doing there is confirming the AIR circuit is free, whereas the pilot jet is the metering for the fuel circuit.

    Also, just coz it’s not blocked doesn’t mean it’s completely clear and operating according to its proper size and flow rate etc.
     
  11. auldblue

    auldblue VIP MEMBER

    Joined:
    Nov 20, 2012
    Cheers Nigel and Toronto, I did the pilots with a strand of wire brush and air. But I’ve a feeling it’s still not 100%.
     
  12. kommando

    kommando

    Joined:
    May 7, 2005
    #78 or 16 thou drill is the only 100% reliable method, even if you can clear it with the correct sized wire all you are doing it pushing the dirt back into the feed gallery and leave it free to move forward and reblock the pilot.
     

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