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1971 Norton steering head bearings removal (2016)

Discussion in 'Norton Commando Motorcycles (Classic)' started by nortonisthebest, Feb 19, 2016.

  1. nortonisthebest

    nortonisthebest

    Joined:
    Aug 1, 2014
    I have a 1971 Norton and I want to powder coat the frame. I don't think I can leave the sealed bearings in the steering head because of the 350 deg heat that will take to cure the paint. How do I remove the bearings without damaging them? How should I reinstall them?
     
  2. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    For what the bearings cost, it's not usually worth attempting to re-use the old bearings. The removal procedure outlined in the manual involves knocking the bearings out using a drift applied to the inner races which can damage the bearings.

    A suitable size tube or large socket just smaller than the bearing outer diameter can be used to fit the bearings.
     
  3. nortonisthebest

    nortonisthebest

    Joined:
    Aug 1, 2014
    Inside the steering head between the two bearings is what looks like a round spacer tube. It is hard work around this spacer however I can move it from side to side but I can only reach the center bearing race with a punch. Is this a standard spacer or did someone add it? I might try heating the outside of the steering head to expand the head for removal or would this damage the steering head?
     
  4. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    It's probably the standard spacer tube.

    I guess you didn't read the relevant manual section on renewing the steering head bearings (section G6)? :? :roll:

    http://www.classicbike.biz/Norton/Repai ... mmando.pdf
     
  5. nortonisthebest

    nortonisthebest

    Joined:
    Aug 1, 2014
    I ordered two new steering head sealed bearings. I'll replace them after powder coating. Thanks for all the info.
     
  6. mschmitz57

    mschmitz57

    Joined:
    Feb 13, 2013
    Yes, usually I just push the tube aside with a long socket wrench extension, then drift the mother out.
    The bottom bearing can become brinelled over time because the balls remain relatively stationary and take a beating creating notchy steering.
    Best to replace them. New bearings are cheap as chips. PN 06-7604

    The new bearings need to be started squarely and evenly. I usually use an old bearing as a driver tool when I knock them back in, or use a block of hardwood. Just make sure to press them in by the outer race. I've used a Park Bicycle Tool bottom bracket tool as a bearing press. But a block of hardwood and mallet works fine. Just be careful not to get the bearing cocked at the start. And hopefully your powder coater remembers to mask off the head tube bearing seats, otherwise you'll have a real headache.

    Good Luck.
     
  7. nortonisthebest

    nortonisthebest

    Joined:
    Aug 1, 2014
    I did as you said. I removed both bearings with very little trouble. I ordered new bearings and with probably install them using a large socket.
    Thanks for your reply.
     
  8. NickZ

    NickZ VIP MEMBER

    Joined:
    Oct 31, 2018
    I haven't tried this yet, but Section G6 does not make sense to me. Even ignoring the spacer, if I have a drift that fits thru the inner race of the top bearing, how is it going to contact the inner race of the lower bearing of the same size to drive it out?
     
  9. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    You put a suitable rod inside to lever the spacer across just above the bearing.
    Once you get some clearance from the first blow to the inner with a drift the spacer will go to any position you want so the bearing can be driven out at something close to parallel to the bore in the frame.
     
    Last edited: Jun 9, 2019
  10. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    The drift needs to smaller in diameter than the bearing so it can be angled to one side to rest on the inner race of the lower bearing Edit: after the spacer tube has been moved.
     
  11. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    Done.
    I hadn't given it to much prior thought but the spacer tube was not to long but to short for tapered roller bearings.

    Where to find shims around 32 mm OD and 25 mm ID, what bikes do I have that might have those shims ? , the answer was in the Moto Guzzi section.
    I had quite a few spare final drive pinion shims.

    IMG_5798.JPG

    IMG_5797.JPG

    I machined a spacer so I could tighten the retaining nut without the lower triple in place, final measurement was 1.5 mm of shimming under the top bearing for a smooth operation lock to lock.
    I can't see how tapered roller bearings could be used with no inner tube and a floating lower triple clamp.

    IMG_5802.JPG
     
  12. NickZ

    NickZ VIP MEMBER

    Joined:
    Oct 31, 2018
    Ok. I was thinking that the drift needed to contact the lower inner race squarely and full circumference, which, of course, is impossible.
     
  13. NickZ

    NickZ VIP MEMBER

    Joined:
    Oct 31, 2018
    I don't have your resources so I will have to start with a longer tube and grind it down to correct length. From your experience, it seems that I can start with a length a little more than 1.5 mm longer than the stock spacer tube 06-7742 (0700100). Would you agree with that?
     
  14. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    If you are using the standard 4203 ball bearing, just assemble it back together as the Norton factory did.
    You will only need shims if you use a tapered roller bearing as the spacer will be to Short due to the inner race top face being 0.85 mm below the outer race cup face, that might raise the ? ..... If 0.85 mm x 2 = 1.7 mm (two tapered bearings) why did I only need 1.5 mm of shim for smooth but firm rotation ? .... Where is the other 0.2 mm and what was it doing to the radial ball bearings I removed, pre loadng them unless the spacer tube is made from some form of springy material that can collapse and then return to length after being removed....... or might explain why the lock to lock was notchy to some degree prior to disassembly.
    Over thinking ? ..... Fit once and forget is my policy whatever it takes in this case.

    IMG_5814 - Copy.JPG

    In this case the shims are under the top bearing race on top of the spacer.
    The bearing was open to the elements at the lower triple so I turned that plastic spacer that fits over the triple and rests against the face of the inner bearing race face.
    I can think of any bikes off hand that have a bearing that can be effected by preload that do not have double fine thread locking rings to do so independent of the triple clamp which would rest on those rings.

    IMG_5809 - Copy.JPG

    With the spacer out the lower nut can never be tight as it should be to avoid bind at the races and the lower triple pinch cap screws would be holding position via the fork stanchions... yikes.. Or clearance set and torqued to spec and going nowhere with the spacer tube in place.

    IMG_5811 - Copy.JPG

    IMG_5807 - Copy.JPG

    As I said on FarceBook, if folk want to leave the spacer tube out with tapered roller bearings that is their prerogative.
     
    Last edited: Jun 12, 2019
  15. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012

    As posted prior, once you lever the inner spacer tube across enough to get access to the inner bearing race for driving out it will be easy... just work around the bearing inner with the drift so it comes out something like even.
    As it gets further out it may want to cock over more as the support in the frame bore it sits in is lessened.

    Come time to fit new (ball ? ) bearings a Isolastic outer ? can be used.
    There are plenty of ways to install the bearings but once started they can be drawn in with two of the Iso ? with a full thread or some such thing which will rest on both the inner and outer races so they can not be loaded... once they seat on the inner spacer its done.
    I personally put grease in the frame bore that the bearing goes in to to make it easier (they should be a decent fit) to install and so there can be no corrosion when the next person changes them out in 50 years time.

    IMG_5815.JPG


    ...... and that is way to many posts for 24 hours !.
     
  16. NickZ

    NickZ VIP MEMBER

    Joined:
    Oct 31, 2018
    Thanks so much for your helpful information. Very relevant to my situation. I found that the bike I am restoring (72 Interstate) has two 30205 tapered roller bearings (which I believe is the same as what you used) but no spacer. I am debating whether to keep these bearings, which appear to have been installed but never ridden, and add a customized spacer, or buy and install the standard ball bearings and spacer. If I stay with the TRB, I will have to create a new, longer spacer because I don't have a source for the shims you used with the standard spacer.
     
  17. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    Nick, in my case I just used a standard 32 mm OD / 25 mm ID Moto Guzzi shim used to shim the final drive pinion roller bearings and the stock tube but I am willing to bet McMaster- Carr would have a ground shim washer or similar on the shelf.

    The stock tube is easy to get from the likes of Old Britts etc.

    I personally think the tapered rollers (even though I am a fan of the Koyo three piece steering head bearings but were not size available) are a step up and using the spacer tube is not only easier but prudent to normal engineering principles especially as the Commando does not have the usual fine thread locking rings as mentioned up the page somewhere.

    It probably took 10 minutes to get a bearing clearance I was happy with but that custom spacer and doing the nut up tight confirmed there was no bind.
     

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