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Leak Down Test (Don't Laugh!!)

Discussion in 'Norton Commando Motorcycles (Classic)' started by click, Jan 27, 2018.

  1. click

    click VIP MEMBER

    Joined:
    Dec 27, 2008
    Thanks for the reply.

    When you say "it amazed me how much the fasteners would turn each time."

    are you adding to the torque and not backing off & then re-torquing again?
     
  2. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Back off and re torque, but noticing the wrench went further on the retorque, sometimes a lot further!

    As an aside, last time I rebuilt the top end I took advice from an ‘old hand’ and over torqued them a little on assembly. But others have warned this could lead to issues.
     
    Last edited: Apr 24, 2019
  3. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Click, is a stock gasket ok with a 79mm bore?
     
  4. click

    click VIP MEMBER

    Joined:
    Dec 27, 2008
    Jim C. said it would be OK, I didn't notice any overhang when test fitting the CH gasket on the barrels.
     
  5. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Cool.
     
  6. click

    click VIP MEMBER

    Joined:
    Dec 27, 2008
    I've sorted a few electrical problems (RH switchgear).

    I've got spark on both cylinders, everything is back together BUT my battery is dead, I think I left the ignition switch on & it's been sitting for 6-7 months!!! Tried smart chargers, normal chargers but it's totally dead, only 1 year old & barely used!!

    I have a new battery ordered, hopefully my next post will be a video of the 880 running!
     
  7. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    “My Kingdom for a horseshoe” !
     
  8. click

    click VIP MEMBER

    Joined:
    Dec 27, 2008
    "For want of a nail"!!!
     
  9. click

    click VIP MEMBER

    Joined:
    Dec 27, 2008
    OK guys, here you go, did it blow up? did the pistons shoot up through the cylinder head?

     
    cliffa, baz and Fast Eddie like this.
  10. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    Nice. Did you put in a new cam? If so, dont let it idle below 2500 for the first 20 min or so.
     
  11. click

    click VIP MEMBER

    Joined:
    Dec 27, 2008
    No new cam, just barrel, & custom pistons

    I'll re-torque head, sort the carbs as they were setup for the 920, tighten up a few more bits & then a road test, can't wait!
     
  12. cliffa

    cliffa

    Joined:
    May 26, 2013
    Great news click. The bike sounds good, I’ll bet you are relieved.

    Cheers,

    cliffa.
     
  13. click

    click VIP MEMBER

    Joined:
    Dec 27, 2008
    Thanks cliffa, relieved is one word you could use:D

    Bank holiday here so got the bike ready this morning & went for the 1st 50mile spin.

    Lots of blasts from 30-50MPH & 40-60MPH and a few 50-70MPH, kept the revs below 4K.

    Bike is running great, slight hesitancy at very low throttle pull, I'll clean out the pilot jets & see if it improves.

    Some video below of bike ticking over.

    Here's some shots of the plugs, what do you guys think??:

    RH plug has a bit of soothe on top ring, porcelain is white, tip is grey
    IMG_4120.jpg

    LH plug has a cleaner top ring, porcelain & tip is the same as the RH plug.

    IMG_4121.jpg

    Here's the video:
     
    Peavey Jeltz likes this.
  14. Peavey Jeltz

    Peavey Jeltz

    Joined:
    Jan 12, 2019
    Click, thanks for keep up this thread. I'm chasing a similar problem on my Atlas. Gives me encouragement that I'll get it sorted out. It does run and ride well until the right side plug starts to oil foul.
     
  15. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
    Check to see if your float and needle heights are even.
     
  16. Peavey Jeltz

    Peavey Jeltz

    Joined:
    Jan 12, 2019
    Single Monoblock, so that's definitely not the issue and it's puffing white smoke not sooty. I've got the thing apart now and both cylinders were pretty loaded up with oil, more than I'd expect find after tearing off a head. Taking measurements and working up a whole new thread 'cause this un's long enough.
     

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