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Front Pulley Issues

Discussion in 'Norton Commando Motorcycles (Classic)' started by swooshdave, Aug 21, 2019.

  1. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    I prefer Duvel or Chimay truth be known.
     
  2. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    1554
     
  3. HRD

    HRD

    Joined:
    Mar 21, 2011
    Have you tried a standard Norton front engine sprocket ( a known good example ) on the crankshaft taper to confirm it is the shaft's taper is the problem it maybe that the belt pulley internal taper is incorrect ? That key is sus if it falls out .
     
  4. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Like I said it fit perfectly on the other crank. I don’t know where a standard sprocket is, probably buried. I’ll see if I can find one.

    New key on the way from Old Britts.
     
  5. 850commando

    850commando

    Joined:
    Nov 1, 2014
    interesting situation...

    i just put my primary back together. i can't recall any specifics about the key but my old one was a sloppy fit and it looked like somebody had been filing on it. so i ordered a new one. the new one was not a tight fit in the shaft... so how tight are they suppose to be (thats the part i can't remember)...

    thanks
     
  6. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I believe the primary purpose of the key is to locate not hold the pulley/sprocket. The taper and nut should do the actually holding.

    Anyone want to correct me?
     
    Fast Eddie, baz and comnoz like this.
  7. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    Snug fit for keys. Not drive fits. One doesn't want them to chatter with vibration. Some applications use wedged keys or shimmed keyways to lock auxiliary items onto shafts to prevent movement. So many ways to screw a pooch that it boggles the mind.
     
  8. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    I’m glad I’m not a pooch.
     
  9. myjota

    myjota

    Joined:
    Mar 15, 2010
    Is there enough material on the pulley, and enough width for the belt, to face the back of the pulley down the make the taper effectively smaller? Would be an simple turning job
     
    johnm, swooshdave and Mic like this.
  10. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Interesting approach. The belt width is exactly the same as the pulley so you can't reduce the pulley width. At the front there's not a lot of room.
     
  11. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    What width is the pulley/belt width?
    With the norvil kit I believe you can run a 32 mm or 30 mm belt on a 32mm wide pulley, I'm not certain on this though
    Cheers
     
  12. freefly103

    freefly103 VIP MEMBER

    Joined:
    Apr 17, 2013
    I dont think myjota means the whole back face of the pulley, just around the hole where it mounts.
     
  13. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Doesn't matter, there's no room to move the pulley inboard. It's already hitting the chaincase now.
     
  14. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    Good luck on the fix Dave. You'll get it worked out.
     
  15. rvich

    rvich VIP MEMBER

    Joined:
    Jul 25, 2009
    Average beer can wall is 0.004. That's pretty thin unless you still have some steel cans around. I'm a big believer in creative play, but mostly I like the idea of having a beer while pondering how to sort out the problem.
     
  16. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Is there an advantage to brass over aluminum in this case?
     
  17. jbruney

    jbruney

    Joined:
    Jan 5, 2019
    Brass is most suitable of the two. Aluminum is soft by comparison. Steel would be best.
     
  18. Dommie Nator

    Dommie Nator VIP MEMBER

    Joined:
    Apr 2, 2013
    Good idea and if facing off the back made it fit but left it too narrow then the outer guide plate could be shimmed to give the width back. Just an idea, or would it throw up other issues?
     
    johnm likes this.
  19. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    Overly complex compared to shoving crap in the gap or getting a blank pulley machined to the right taper.
     
    Last edited: Aug 24, 2019
  20. Nortoniggy

    Nortoniggy

    Joined:
    Nov 17, 2010
    Don't you folks the other side of the pond still have food in tins/cans? They are mostly still steel. Baked bean cans have provided me with the odd steel shim over the years.

    Aluminium wouldn't be tough enough I reckon.

    Ian
     

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