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Swing arm/chain case interference and more etc (2010)

Discussion in 'Norton Commando Motorcycles (Classic)' started by MexicoMike, Feb 26, 2010.

  1. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    You know, sometimes it's best to NOT know what's going on! ;)

    In my swing arm work (other thread), I discovered when I tried to re fit it, that the swing arm right side interferes with the inner chaincase. There is actually a round "end of swingarm" print worn into the case so obviously it's been doing that for a long time. ALSO, the rear chain has worn a fairly substantial grove into the chaincase as well. So I have two questions (I have referred to the parts and service manual and don't see any answers for this)

    1. Is there any standard "factory" way to adjust the distance between the chaincase and the cradle/engine - shims or whatever?

    2. Are there shims under the rear drive sprocket that allow it to be moved toward/away from the chain case? Of course, if there are no shims normally there, then there is no way to move the sprocket further away from the chain case on it's own.

    Of course the fact that the chain badly groved the chaincase AND the fact the swingarm did the same indicates to me that the chaincase is just flat-a$$ too close to the cradle.

    So what's the solution?
     
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  2. BrianK

    BrianK

    Joined:
    Jun 14, 2007
    Mike, you mean the inner primary case? That gets shimmed on the central bolt, behind the inner case. Do a search, there should be plenty of learning on it. I haven't had to adjust mine (has three shims and works fine) so I have no personal experience. Good luck.
     
  3. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Brian - yes, inner primary. I just finally found on the parts diagram a "Chaincase center stud shim" with the number shown as "as Required." Some additional ones appear to be required. I'll do a search as well, thanks.
     
  4. BrianK

    BrianK

    Joined:
    Jun 14, 2007
  5. grandpaul

    grandpaul VIP MEMBER

    Joined:
    Jan 15, 2008
    Yep, fit up the chaincase without any spacer washers on the stud, snuggle up the three inner chaincase bolts without thier tab washers and then measure how much shimming you need to do. You should also be able to see at that point that your swingarm clears.

    Fitting that sucker up and tightening it down without shimming it, will definitely result in cracks around the center stud boss, cracks around the 3 bolt holes, and some serious rubbing at the swingarm pivot. VERY common on bikes that have been messed with.
     
  6. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Thanks Brian/GP

    I loosened the center stud but the chaincase did not move away from the cradle at all as I would have expected it to if there were insufficient spacers. The front of the inner case is firmly mounted to the engine and it looks just fine. The only obvious answer that I can see is multiple gaskets between the eng and inner chanicase and then additional shims at the center stud to space the chaincase out but this is a half baked answer. There must be a sensible reason that even with the chaincase properly mounted to the engine and the stud loose, the inner chaincase is too close to the cradle.

    The bike was completely assembled from components - it is not a matching parts bike - by the dealer I bought it from. They convinced me it was superb and I didn't care about matching numbers. But now everywhere I look I continue to find more indications that they didn't know or didn't care what they were doing.

    So is are there any other cradle/engine alignment issue that could cause this? Heck, I could put it back together as it was and forget about it - the chain grooves and swing arm "hole" in the inner chain case aren't going to get any deeper but I just don't like things that are wrong! :(
     
  7. grandpaul

    grandpaul VIP MEMBER

    Joined:
    Jan 15, 2008
    Are you sure your inner primary case isn't cracked and/or warped from the abuse?

    If you try to shim it all out to clearance it, you may end up with the primary chain and/or clutch basket sawing into the face of the chaincase.
     
  8. ludwig

    ludwig

    Joined:
    Aug 30, 2006
    I almost dare not say it , but it is not impossible that the 3 bolts that hold the rear of the engine to the cradle where loose sometime in the bike's past , and that the holes in the plates and/or engine are worn oval .
    Check if the crankshaft sprocket and clutch basket are in line to begin with .
     
  9. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    "Are you sure your inner primary case isn't cracked and/or warped from the abuse?"

    It's not cracked. I guess it could be warped. If I try to pry the chaincase out at the back end with a hammer handle it will only flex maybe 1/16" using "reasonable" pressure. Anything more than that would really strain it and probably result in cracking at some point. The case doesn't leak at all which would seem to me to indicate that it's not warped. Tomorrow I'm going to carefully examine the cradle/engine to see if it's possible that the engine is angled somehow which could cause the problem...

    "Check if the crankshaft sprocket and clutch basket are in line to begin with ."

    I'll do that Ludwig, thanks!
    :(
     
  10. daveh

    daveh

    Joined:
    Jan 22, 2008
    Brian — I had the same imprint from the end of the swinging arm on my inner primary case. I fitted an extra gasket (approx. 15 or 20 thou, can't remember) between the crankcase and the inner primary and re-shimmed the inner case against the stud on the cradle. This helped to create a small amount of clearance. Why not try making a second gasket, bolting it up temporarily and with no pressure on the mounting stud on the cradle. Then, with a feeler gauge between the end of the swinging arm and the inner case, see if you have some clearance. If you have a gap, however small, it should help prevent the chain from rubbing as well. But I guess the chain has worn its own clearance by now! I assume you have a standard 530. I run a heavy duty 530 which is slightly wider. If the primary is apart, it's an opportunity to try this out. I checked very carefully that the extra shimming did not interfere with anything. In my case, it was OK, but of course, it's a point to bear in mind.

    Dave
     
  11. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Dave,

    I agree this is workable but it SHOULDN"T be necessary though I may end up doing it...

    Thanks

    (Mexico)Mike
     
  12. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Further looking makes it appear to me that Dave's solution is the only thing that will work Though I can't figure out why. Did Commandos come from the factory with drive chains and swing arms grooving the inner chaincase? ;)
     
  13. splatt

    splatt

    Joined:
    Jul 14, 2008
    more than likely yes, are you running an absolute std 530 rear chain :?: most heavy duty ones rub
    If your front engine mount is out of alignment it will cock the engine out of alignment,have also had to fit 2 gaskets.
    It's easy to run a straight edge from crankcase past the mounting stud to see what size of shims are required, just allow for the recess in the inner primary
     
  14. bpatton

    bpatton

    Joined:
    May 19, 2009
    I've seen it on my bike and a couple of others. There are signs of shuffling on the case and the cradle and the holes are oval. I went with oversize bolts reamed to fit and the stock bolts need to be replaced with ones with the right grip length so the cradle isn't riding on the threads.
    For a few extra pounds in weight they could have avoided a lot of problems with the cradle. Did Colin Chapman do any consulting work back then?
     
  15. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    "Did Colin Chapman do any consulting work back then?"

    LOL! Good One!!!
     
  16. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    OK, fixed (temporarily). I pulled the chaincase and determined that the engine/chaincase shimming needed was the thickness of two layers of Oreo cookie box... yes, really (Don't have any gasket paper). I also adjusted the shimming on the central bolt. That removed the chain from hitting the case but only because there is already a groove there. It wouldn't have been near enough with an undamaged inner cover. THe swingarm also now does not touch the chaincase by about thickness of one piece of cookie box. So I'm still wondering how it is supposed to work from the factory. If the chaincase was shimmed out any further, the primary chain would hit the bolts and/or the side of the case. Frankly, I'm not sure it won't graze the case when running though it clears when rotating it by hand. But if I push the chain over I can make it hit the bolts and the case. Don't know how much it shifts sideways when running.

    I say it's fixed temporarily because I need to take it back apart when I change the sprockets for 520 chain in a couple of months and renew all the swingarm parts and add the clamps to the swingarm cradle tube. I found that that the front sprocket is shot - "hooked teeth." But that will be addressed with the chain mod. I'll also put in real gaskets for the chaincase/engine! I used Permatex ultra gray at the circular joint where the case mounts to the engine - just at the circle joint, not on the back side of the case agains the "gaskets." So there won't be any chaincase lubricant getting to the gasket

    When I put the swingarm back on, and before tightening the center bolt and the two added bolts, the swingarm rattled in the cradle so I guess the cradle is worn. After tightening the bolts there was no play in the swingarm at all.

    Thanks for all the guidance!

    Here are some pics

    Here's the swing arm imprint in the chain case and it was still rubbing.
    [​IMG]
    The chaincase with the groove worn by the chain
    [​IMG]
    The oreo cookie box gaskets before final trimming!
    [​IMG]
     
  17. batrider

    batrider

    Joined:
    Aug 9, 2008
    Maybe you are using a chain with thick plates? On mine I ended up getting another Renold chain because most of the big name brands like Diamond were too wide and rubbed. I think RK Chain will also work. I have the master link turned so the clip is on the inside too.

    You're about right on the clearance from the swingarm end cap to the back of the chaincase. About 1 Oreo box thickness!
     
  18. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    "I have the master link turned so the clip is on the inside too. "

    That's a good idea! I'll do that. I wonder how the 520 X ring chain compares with standard 530 as far as clearance. The chain on the bike at the moment is 530 RK. But as I said earlier, since the chain AND the swing arm hits the chaincase, I believe there is some fundamental issue here with the chaincase mounting on this bike though I don't know what it is. The cradle holes for the engine mounts were not elongated.
     
  19. pete.v

    pete.v

    Joined:
    Oct 31, 2009
    Now that you have changed the inner primary case (shims, gaskets, spacers, cooky dough, etc whatever), you will have to check for flatness for the outer cover or it may leak, (Unless you have a belt drive of course). The spacers/shims on the center bolt before the inner is placed, are for adjusting the inner case from warpage.
     
  20. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Will do! As I have said before, a glass plate and wet/dry sandpaper should have an official Norton tool number. I have probably used it more on the Commando than any other "special tool!" :)
     

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