1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Mk3 left side gear lever leak

Discussion in 'Norton Commando Motorcycles (Classic)' started by p400, Apr 23, 2019.

  1. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    I have a leak coating the left exhaust coming from left side gear lever.
    I don't see a seal relating the outside primary case.
    What is the fix please?
    20190423_Mk3GearLeverLeak.jpg

    Looking further I find it.

    Group10Gearboxseal.jpg
     
    Last edited: Apr 23, 2019
  2. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    Can this seal (#10) be replaced externally, without pulling the outer primary?
     
  3. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004

    Possibly, but it's not very wide so could be difficult to drill and pull out with self-tapping screws.
     
    The Buckeye Rider likes this.
  4. The Buckeye Rider

    The Buckeye Rider

    Joined:
    Jan 1, 2005
    The seal maybe could be replaced without pulling off the cover but the seal is probably leaking because the bushing #9 is worn out.
    This would be a good time to open it up and service the primary chain tensioner even though the workshop manual states "no maintenance required".
    Ride On
    Dave
     
    dougmatson likes this.
  5. dynodave

    dynodave

    Joined:
    May 28, 2003
    If the bike has ever been tipped on the LH side, You have a distinct possibility the cover is cracked where the seal boss lives. I've seen a few and it is a nasty weld and machine job to fix...unless you want the JB weld method, which I have never tried.
    Good luck.
     
  6. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
    Age of seal means replace it if leaking. Matter of course in any repair.
     
  7. chaztuna

    chaztuna VIP MEMBER

    Joined:
    May 5, 2017
    Also inspect the bushing carefully. Even the best seal will leak with a worn bushing.
     
  8. p400

    p400 VIP MEMBER

    Joined:
    Jul 14, 2014
    What is the tooling and procedure for replacing this outer primary case shift shaft bush (9)?
    Which direction is the bush moved to remove/replace?
    Any heat involved in accomplishing best procedure?
    Arbor press? hyd press? mandrels?
    And, god forbid, any competent informative photos of anyone actually performing this job?
    Or even a Utube shakey video?
    Happy Mothers Day

    [​IMG]
     
    Last edited: May 12, 2019
  9. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Either way by the looks of it as it's just a parallel bush and no shoulder in the case.


    Probably preferable/easier than doing it cold.




    14mm and 9/16"AF, 3/8" square drive sockets I have are both the correct diameter.
     

Share This Page