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Exhaust Chirping and Misfire

Discussion in 'Norton Commando Motorcycles (Classic)' started by Tornado, Jun 30, 2019.

  1. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Been having trouble with the mkii 850. Recently fitted un balanced headers and dual Amals (originals that came with bike last year).

    Right side has a chirp as seen and heard here:



    Have not been able to dial it out via air screw and slide stops.

    Also note bike has a misfire which is making riding it unpleasant. Seems to happen under most rpms and gets worse above 4k.
    Running a Wassell EI, similar to boyer. Connections seem good. Also getting oil leakage front fins of head. I tried sealant under the two front head nuts and torqued all fasteners. Leakage partially reduced but still there.
    Thoughts? Headgasket time?
     
  2. ELLIS

    ELLIS

    Joined:
    Jan 6, 2017
    Hi Tornado

    Can't help you with that bird problem on the right, But the head gasket oil leak may just need the head fastenings re torqing. I had to re torque the head 5 times until it stopped leaking and it still remains oil tight 1 year on.

    ELLIS
     
  3. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    Are exhaust pipes both discoloured equally ? .... if your EI similar to Boyer it hard to tell if your wires are fractured with just a look ....
     
  4. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Re torquing. Done that a few times now. First time a year ago before current leaks. There were a couple of fasteners quite loose back then.

    Header bluing started when I first swapped them on while still running single amal. Rightside blued quite bit. Dual carbs now showing blue but hard to know if from earlier settings or current. Need to deblue to rerun that test.
    Also forgot to mention right plug sooty left plug tan to chalky.

    EI similar to boyer in terms of setup but it appears. Better made with epoxy encapsulated stator plate.
     
  5. N0rt0nelectr@

    N0rt0nelectr@ VIP MEMBER

    Joined:
    Sep 15, 2014
    Spray a little carb cleaner on the carb joints, see if the idle picks up. Might be an intake leak.
    John in Texas
     
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  6. ELLIS

    ELLIS

    Joined:
    Jan 6, 2017
    Have you checked the float levels to make sure they are both the same, its a good starting point to get them correctly set.

    ELLIS
     
    Torontonian likes this.
  7. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Floats were checked for spec height as per Bushman guide at 2mm below bowl lip. Carbs fitted with all new gaskets, jets, needles and also tried new anodized Wassell slides.

    Will try more air leak testing. Hope not to set things on fire like I managed last time :)
    Have heard spraying the head/block joint can reveal headset leaks. Have not tried that.
     
  8. ashman

    ashman

    Joined:
    Jul 11, 2010
    The bottom studs on your tappet covers could be leaking they need to be pulled out and put some sealent around the stud that screw into the head, just sealing the nuts won't stop the oil leaking from the studs, when they leak it looks like its the head gasket that is leaking, got caught out with that one a long time ago and kept thinking it was my head gasket blown.
    As for misfire could be air leak or carby set up and it could be ignition faults, start looking at one first and work your way till sorted, blocked jet to fratured wire to faulty coil, you just got to go through everything but one step at a time till sorted.
    Exhaust leak could also be a problem but dought that would cause a misfire right through the RPMs.
    If the bike runs ok when first started and don't start to misfire till warmed up it could be a faulty coil, really it guessing at the moment, could even be a faulty plug and even new plugs can be faulty out of the box, the wires from your pick up could be worn from where it comes out of your points cover, step by step going through things and you will get it sorted, it can get very frustrating at times, but don't get angy if you do just walk away from it and think about it.
    I had 33 years trouble free from my old Boyar and was still working when I replaced it with the JH maggie so not all Boyar's had faulty wires.

    Ashley
     
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  9. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Thanks all.
    Re oil leak, it looks very much like starting at the head nuts front side. It is these I removed and put copper rtv hitemp under. Seemed to reduce. But not cure leak. Will look at rocker cover studs.
     
  10. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    Switch , plug leads side to side see if soot follows , etc. .... eventually the light will go on and you be happy again .... be sure to be methodical in your approach , good luck
     
  11. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    here are the two plugs after two hours running around town and up and down a mountain:
    Sooty from right side. 15619340875086888246571324197518.jpg
     
  12. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Took left exhaust rocker cover off to see what nut thread stud was. Nothing I could lay a hand fits that fine thread stud so no change to remove right now. Might find something bolted elsewhere on bike to fit?
     
  13. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    And kinda bummed no one has commented on my new roadster tank on bike for first time yesterday.

    Got the requisite fuel seeping from tank cap. Need to fettle it some I suspect. Seal is new.
     
  14. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    Well it is a nice looking tank while I did notice ,had prior knowledge and was dialed into getting a look at pipes , obviously you got an issue on right side .... only time I had plugs like that had a fractured wire on old Boyer , found it after trying lots of other stuff first ... not to say that your issue though
     
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  15. 850commando

    850commando

    Joined:
    Nov 1, 2014
    wow nice TANK :D
     
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  16. ashman

    ashman

    Joined:
    Jul 11, 2010
    I just use my small vice grips just lock the grips at the end of the jaw where the stud has no thread and they will come out easy.
     
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  17. Onder

    Onder

    Joined:
    May 11, 2010
    Hey, nice paint on that vise! :)
     
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  18. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Update:
    Been ignoring the bike for about 1 1/2 months. Today I went through a few checks. Coil resistance on primaries seems just in spec on left at 1.9 Ohms while right is 2.1. Tried swapping plug leads to opposite sides and after doing the idle jet poke and carb spray through fired her up on second kick. After warm up, noted the chirping had seemed to disappear from right and was occasionally heard on left side. Note this was with fresh plugs as well. After tweaking idle air screws I found the chirp could be dialed out by going bit leaner. Swapped plug leads. Back to correct sides. Went for a good distance ride. Chirp seems cured. Misfiring seems to be gone except occasionally at around 5k rpms.
    Could electro magnetic interference give rise to misfire on these EI's? I'm not running resistor plugs or caps.

    Still getting oil seeping front fins after the lower cover studs pulled and sealed. Not quite sure how they can contribute to leaks as any oil going down those threads will end up inside the rocker casing not outside it, correct? Oil does not appear to be on outside of rocker cover lower edges.

    Will try to go on a long ru n tomorrow to see how she goes. Must say it feel good to be back on the Norton after doing cross Canada on the Bonne.
     
    Last edited: Aug 26, 2019
  19. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    Be surprised if you don’t fall in love all over again , thanks for update as well .... also ,once again half way cross Canada almost ...you got the newer portion under your belt and saved older bit for another time ...haha!
     
    Last edited: Aug 26, 2019
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  20. oldbeezer

    oldbeezer VIP MEMBER

    Joined:
    Nov 2, 2017
    could the exhaust chirping possibly be an exhaust leak? just a suggestion.
    NICE tank btw.
     
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