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Gearbox layshaft bearing replacement

Discussion in 'Norton Commando Motorcycles (Classic)' started by Steves, Sep 14, 2017.

  1. Steves

    Steves

    Joined:
    Oct 16, 2016
    So the gear box broke. Usual symptoms starting with Kickstarter tapping back of the leg, then noise etc.

    Initial thought layshaft bearing. Further Initial thoughts are to do it with gearbox in the frame, if however I need to take the main shaft out is that going to create a problem in being able to dismantle primary drive. I suppose I could loosen everything up on the primary side in anticipation, but leave in situ.
     
    MichaelB likes this.
  2. Mr. Rick

    Mr. Rick VIP MEMBER

    Joined:
    Feb 6, 2009
    When Steve helped me replace my layshaft bearing, we did it with the gearbox still in place.
    Just the bearing replacement would have been somewhat easier out of the frame, but the gearbox removal and replace is itself rather tedious.
     
  3. batrider

    batrider

    Joined:
    Aug 9, 2008
    I did it in the bike with no problems. I would recommend buying or making a clutch lock tool. It can be made by bolting an old plain plate and friction plate together. The store bought one has a really long handle that can rest on the rear iso thru bolt nut. Nice! I think it is from Andover. I replaced my mainshaft and sleeve gear bushes also. It was bent with a twist to it so unfixable. I had the transmission gears and layshaft out before deciding to go all the way so needed the tool to take the primary apart.

    Russ
     
  4. Steves

    Steves

    Joined:
    Oct 16, 2016
    Thanks guys, ended up stripping it down in situ this afternoon. All pretty straight forward, ordering parts.
     
  5. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
    Heat and cold are your friends.
     
  6. NortonMKIIA850

    NortonMKIIA850

    Joined:
    Jul 20, 2017
    Heat and cold alone were oblivious to my needs when I wanted to replace my layshaft bearing this summer, I ended up cooking up a home-made slide hammer: be prepared for some creativity in removing the old bearing, point being not to give up, it can be done! I tried removing the gearbox, but that proved to be such a PITA that I shall henceforth do all gearbox work with the box in place, unless it's the box itself that needs replacing ...
     
  7. Adam_R

    Adam_R

    Joined:
    Nov 20, 2015
    i think the manual states to put up the are then drop the case. clearly they had never had to do one that wouldn't come out.
    i made up a puller to extract mine
     
  8. Steves

    Steves

    Joined:
    Oct 16, 2016
    So yeah heat and a threaded bar with bits added did the trick. So last question on this matter, I have done some research there seems to be pros and cons re ball or roller bearing replacement.

    The bearing (layshaft) I took out has done about 10k miles. It's a caged ball bearing with a half shield, FAG, it looks in good nick until you spin it then it sounds like a bag of nails and feels notchy.

    What it is the opinion, roller or ball?
     
  9. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
  10. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    If a ball bearing (my preference) it should be a FAG 6203 TB P63.
     
  11. tpeever

    tpeever

    Joined:
    Aug 21, 2006
    Much easier to do out of the bike. You can heat the entire box on a gas grill or in the oven to remove and install bearings.

    I used the upgraded FAG roller bearing when I did mine
     
  12. robs ss

    robs ss VIP MEMBER

    Joined:
    Aug 16, 2016
    L.A.B., what is your rationale for preferring balls over rollers?
    I'm not disagreeing, just interested as this is a job I will do on my 650SS soon.
    Cheers
    Rob
     
  13. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Mick Hemmings recommends the FAG 6203TB P63 phenolic cage ball bearing over the roller as he says (in the NOC Norton Gearbox Servicing video) that he's never known one to fail even under racing conditions. The ball bearing often doesn't require shimming, unlike the roller.

    Mick's own words from the NOC video:
    *(Must be getting on for around thirty years by now)

    https://www.123bearing.co.uk/bearing-62 ... 63-FAG.php
     
  14. Steves

    Steves

    Joined:
    Oct 16, 2016
    So I ordered the ball bearing from Mick Hemmings, took about 4 mins of pleasant conversation on the phone. I tried that 123 bearing outfit, about 15 mins of confusion (I didn't want to register on the website) on the telephone, it's based in France.

    There are some good threads on here about the layshaft bearing, plus some good how to's on the inter web.

    I am wondering whether to offer up the bearing on the shaft to the gear box or bearing in first then shaft. I don't have a problem freezing the bearing but would not want to apply much if any heat to it.

    Will play around with it when it arrives, but thoughts?
     
  15. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    The 123 site was just to show an example of the bearing.


    That's how Mick does it in the video, and how I did it, that was sometime before I watched the video.
     
  16. Steves

    Steves

    Joined:
    Oct 16, 2016
    I found that 123 site independently of your link, so into habit of Googling stuff it can, if not careful, lead you up the garden path.

    And thanks will try it on the layshaft and then into case.
     
  17. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    When doing the laysahft bearing on a gearbox with 12,000 miles, is it best practise to just perform the full overhaul with all new bushes, springs, seals, bearings or is it quite reasonable to just go after the layshaft bearing and resuse existing components save for seals/gaskets?
     
  18. kommando

    kommando

    Joined:
    May 7, 2005
    Bearing seals and gasket should do it.
     
    Tornado likes this.
  19. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004

    The kickstart pawl, layshaft 1st gear bush and as a precautionary measure, at least the 04-0038 'hairpin' ratchet spring but preferably all springs.
     
    Tornado likes this.
  20. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
    Freeze the bearing. Heat the case area with a heat gun. Work quickly before the 2 equalize temperatures from their mutual contact.
     
    Steves likes this.

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