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Installing Bronze Swingarm Bushings and Setting Sideplay

Discussion in 'The Garage' started by YamadudeXS650C, Dec 28, 2017.

  1. YamadudeXS650C

    YamadudeXS650C Central New York XS650 Top Contributor XS650.com Supporter

    I thought I'd compile the essential elements of the swingarm procedures from my other recent thread

    http://www.xs650.com/threads/yet-another-swingarm-bushing-thread.51061/

    ....into a more coherent, single post for those who might want to read the info more easily for their own installation.

    This applies to all XS650 years, and I used Mikes' Bronze bushings, purchased recently.

    I did some measuring of dimensions to see exactly what I had:

    The proper, expected dimensions of this bushing are:

    Length 40mm
    ID 22mm
    OD 28mm
    Collar thickness 2.6mm
    Collar OD 34mm

    Using a new, calibrated Fowler, I got these measures at 65 degrees F:

    [​IMG]

    Bushing One:
    Length 40.06 mm
    ID 22.03 mm
    OD 28.04 mm
    Collar thickness 2.50 mm
    Collar OD 34.07 mm

    Bushing Two:
    Length 40.03 mm
    ID 22.05 mm
    OD 28.05 mm
    Collar thickness 2.60 mm
    Collar OD 34.10 mm

    I noted the largest variation in bold.

    The OD increased on both bushes by .02 just in front of the collar.

    The old nylon bushes tend to be really stuck in there. Make cuts like in the photo below to relieve the tension of the material. Cut almost down to the metal. Then heat with a propane torch until the grease boils, but before the paint gets singed. Knock it out with a long drift. I used a section of copper water pipe.

    [​IMG]

    After 24 hours in the freezer, the OD of the new bronze bush was reduced by .04 mm.

    Reheat the arm with a torch and assemble an installation tool made of all-thread, fender washers, and two nuts.

    [​IMG]

    Quickly assemble the tool and your cold bushings. I pressed both at once, which worked, but the torque required in the last 1/2 inch became very strenuous due to the cooling of the arm and warming of the bush.

    [​IMG]

    I suggest pressing one at a time.

    The pivot tube should fit nicely, smoothly. Some have reported having to do a bit of machining/reaming of the bushes to get a good fit. Sometimes the pivot tube is badly rusted; in that case, replace it.

    [​IMG]

    Aligning the tube and the bushing at one end ("flatting them"),

    [​IMG]

    ....a measurement can be easily made at the other end with a feeler gauge.

    [​IMG]

    [​IMG]

    I am inclined to suggest a target figure of .008 and a range of .006" to .010" for this pre-assembly sideplay or freeplay, based upon my experiences and measures taken during two installations, and the technical information available to us.

    The .040" figure found in your Yamaha Service Manual is a wear limit for inspection purposes to be applied later, after many miles of use, and therefore not a figure which we would want to be using when doing our pre-assembly bench set-up.

    The sideplay or freeplay is the distance the pivot tube emerges past the collar of the bushing when you set it up on the bench as I did in the photos. This distance becomes your sideplay. You might have to add a shim if your sideplay comes out to be larger than .010.

    To quote 5T,:
    "The shims are actually used if the pivot tube is too long compared to the swingarm/bushing assembly. They are installed inside the grease seals. They have an I.D. big enough to go over the pivot tube - they don't shim against it. This doesn't happen on most swingams so you don't find the shims very often. You need to thoroughly clean the old grease seals and look inside them to see if shims are present. Most probably get tossed out with the old grease seal because folks aren't even aware they might be in there. Out of the half dozen of so swingarms I've taken apart, I only found shims in one."

    On one of my installations, the sideplay was too small, so I carefully filed down the collar until I achieved the correct play. You can see this in the last photo, above.

    Next, install the swingarm, using the new end seals if yours were at all bunged-up.

    5Twins offers the following torquing procedure
    to assist in fine-tuning your sideplay:

    " When installing the swingarm, I would use the pivot bolt torque range given in the '77 torque spec chart (36-58 ft/lbs), not the single value given in some of the other years manuals (something like 47 ft/lbs). When you install one of these, the usual procedure is to torque the pivot bolt until it is in the specified range and so that the arm very slowly falls under it's own weight. That may not happen exactly at 47 ft/lbs (probably won't). It will probably require a bit more or less than that. If it stays loose above the max torque spec, you've got too much play. If it binds up completely before you even reach the minimum spec, you don't have enough play."

    The results of my recent torquing procedures, per the recommendation of 5T:

    > The 1980 was set at .008, and the arm fell slowly at about 38 ft. lbs.
    > The 1976 was set at .010, and the arm fell slowly at about 42 ft. lbs,
    the results of which seem to validate that the .006 to .010 range of pre-assembly sideplay is a good starting point.

    fini
    .
    .
     
    Last edited: Dec 29, 2017
  2. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    Excellent write-up Dude. This will be very helpful info for a great many people.

    Pete
     
    YamadudeXS650C likes this.
  3. YamadudeXS650C

    YamadudeXS650C Central New York XS650 Top Contributor XS650.com Supporter

    Thanks, Pete, that was my hope.
     
    timbeck, JRP01 and gggGary like this.
  4. JRP01

    JRP01 XS650 Enthusiast

    Great thread. Very helpful to an XS neophyte.
    Thanks
     
  5. 59Tebo

    59Tebo 59Tebo Top Contributor

    You rock, 'Dude! And so do the rest of yous. These articles are timely and useful to experienced restorers and neophytes (me) alike. Like I said before "...it's almost like cheating!..." Hats off to all you contributors! :rock: :cheers: :bow::bow2: :woowoo:
     
  6. YamadudeXS650C

    YamadudeXS650C Central New York XS650 Top Contributor XS650.com Supporter

    Pleased to receive the positive feedback, fellas !
    This community is all about sharing info and supporting others.
    Receiving knowledge from others is how I got started with these very cool machines, years ago.
     
    Mailman, JRP01, TwoManyXS1Bs and 3 others like this.
  7. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    Hi 'dude,
    nice detailed write-up, thanks for posting. But it don't fix what I reckon to be a serious
    design flaw.
    Many XS650 swingarm pivot problems are caused by the throughbolt losing it's bite on the bearing sleeve so
    the sleeve can pivot with the swingarm. That leaves the sleeve to bushing bearing not working at all so the
    actual bearing is between the throughbolt OD and the sleeve's bore which ain't a particularly tight fit which
    in turn makes the bike corner all funny.
    The next XS650 swingarm bushing fix I do will have a solid bearing rod instead of a sleeve. Tap each end
    M16, grind the throughbolt stop off the left side throughbolt hole, reef in a grade 8.8 M16 bolt each side
    & reef 'em up good and that bastard ain't gonna turn, no way. Drill & tap the swingarm cross-tube for
    a grease nipple to complete the job.
     
  8. Paul Sutton

    Paul Sutton Buckhorn Gang Member Top Contributor

    I enjoyed this write-up Yamadude - well done! I have a concern regarding the bearings that are on the market. Some have a spiral cut on the outside, some cut on the inside, others have drill holes and a slot on the inside. Below Is a a photo of one example that seems to make sense to my form of logic. Is this the correct style to use with the lubrication groove cut on the inside? or is there a better option out there?

    [​IMG]

    Thank you for an suggestions.
     
    YamadudeXS650C likes this.
  9. Paul Sutton

    Paul Sutton Buckhorn Gang Member Top Contributor

    Fredintoon I like your thinking. What is the function of the sleeve in the original setup? Does it add extra rigidity by transferring the loading/twisting across two bearings? Should the sleeve actually be fixed to the bolt shaft with Loctite so the bearing functions correctly in the original setup?

    Edit: is the sleeve locked in place solely by the clamping effect of the frame when the bolt is torqued? That would explain the specification for how much the sleeve sticks out at each end. If so then the sleeve not rotating in the bearing is probably due to it being too short, damage to the faces on the frame, or the torque setting too low???
     
    Last edited: Jul 21, 2018
  10. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    Great write up 'dude! You mostly cover the following, just amplifying a bit.
    Dunno Fred if you follow the set up procedure it all works well. I have found frames that were just too wide between the flanges and used a shim to get the clearance close before reefing on the pivot bolt/nut. (This is completely separate from the bushing/sleeve shimming/shaving sometimes needed.) Controlling that clearance keeps the amount of nut tightening to stop the sleeve from turning quite reasonable. On the brass bushing lube channels I'll vote for the inside spiral but if you occasionally grease you should be good. Of more concern is bushing dimensional tolerances, there are bushings out there that are unusable as shipped. Machining them to correct dimensions can be beyond the typical DIY'r and a problem often not spotted until after they're pressed into the swing arm.
     
    Last edited: Jul 21, 2018
  11. grizld1

    grizld1 Grumpy old man Top Contributor

    Your guess is correct, Paul. When things are properly assembled, the "sleeve" (or "inner bushing" in Mama Yama's parts books) locks against the rubber mounted thrust washers on the ends of the swingarm and is clamped in place by the swingarm bolt.

    Gary, re. bushing flange dimensions, the practice I follow is to measure flange thickness on both bushings and swingarm pivot width before installation (a 12" caliper is your friend here). Add those measurements and compare the total to inner bushing length. The ends of the swingarm pivot are chamfered and the material is pretty soft. If there's inadequate clearance, clamp the swingarm in a vise and apply a good flat file. It doesn't take many strokes to get 'er done, so keep the caliper handy and check often. Then install the outer bushings.
     
  12. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    Grzld the flange thickness is the easy part, I have a set here with a ridiculously small ID and large OD, they would need accurate machining before an install. That pair just sits in a parts bin.
     
    TwoManyXS1Bs and grizld1 like this.
  13. 5twins

    5twins XS650 Guru Top Contributor

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    All of the aftermarket bronze bushings I've seen have the lubrication swirl grooves on the inside, and that is where they should be. You wouldn't want them on the outside, that part is a press fit into the arm and doesn't move. Or at least it shouldn't if the fit is correct. Why pump grease into it and possibly facilitate it's movement? The I.D. of the bushing is where lubrication is needed. It rotates around on the sleeve. Now let's talk about how to properly achieve that.

    The pivot bolt has grease fittings on both ends and cross-drilled holes about 1/4 of the way in so grease can get pumped into the arm. This fills the area between the bolt and pivot sleeve .....

    [​IMG]

    The pivot sleeve also has holes drilled through the sides (blue lines below). These deliver grease into the bushings. They are located so that they fall about halfway into each bushing .....

    [​IMG]

    The stock bushings are designed to get their grease like this, midway into the length of the bushing. They have one wide grease groove there, running parallel to the top and bottom of the bushing .....

    [​IMG]

    But, this greasing set-up can present issues when trying to grease the new bronze bushings with their swirled grease grooves. They were designed to get their grease supply from the ends, not the middle. Obviously, you won't be getting any grease into the top ends of them since they're covered and clamped against the frame. That just leaves the bottom or rear for grease ingress. The stock grease holes on the pivot sleeve may get some grease in there, but only if they happen to fall on a swirl groove. Don't count on this.

    A better way is needed, a way to deliver grease to the rear or bottom of the bushing. There are a couple ways to accomplish this. I recommend doing at least one but I usually do both. First, you can add a couple more holes to the middle of the pivot tube (red arrows above). That will allow grease into the center of the arm and from there, it can be forced into the backs of the bushings. The second way is to add a grease fitting to the bottom center of the swingarm pivot area. To insure enough material thickness so the fitting doesn't protrude into the arm, place it at the edge of the gusset plate attached to the cross tube .....

    [​IMG]

    I like to use a 45° angle fitting faced to the rear for easy access .....

    [​IMG]
     
    Last edited: Jul 21, 2018
  14. Paul Sutton

    Paul Sutton Buckhorn Gang Member Top Contributor

    Thank you very much 5twins for the explanation and permanent fix ideas. I see that the central channel cut in the original bearings is what's needed to overcome the issues with aligning the grease feed holes. I had wondered how it all worked. That 45 Degree nipple fits nicely and easy to get to - well done.
     
    robinc likes this.
  15. Paul Sutton

    Paul Sutton Buckhorn Gang Member Top Contributor

    5twins, I guess that your modification of extra holes is what is needed to use these bearings:
    [​IMG]
     
  16. Jim

    Jim The thrill of victory and da agony of da feet. Top Contributor XS650.com Supporter

    Another way to ensure adequate lube to the bushing is to machine a groove into the steel bushing. That ensures there's always a path to the spiral groove. I seem to recall you have a lathe Paul?

    MVIMG_20180226_165350.jpg
    Here' s how I did it.... comment 648
     
  17. 5twins

    5twins XS650 Guru Top Contributor

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    Yes, I feel some sort of mod is needed to insure proper lubrication for the swirled groove bushings. Most of us don't have a lathe but anybody can drill 2 extra holes in their pivot tube.
     
    Paul Sutton likes this.
  18. Paul Sutton

    Paul Sutton Buckhorn Gang Member Top Contributor

    Oops, I forgot to explain my thinking with the bush I showed in the above photo. I see two options based on 5twins hole drilling:
    1. Use existing grease nipples and drill the extra holes in the middle of the sleeve
    2. or just add the new grease nipple as per 5twins ideas
    Both of this options force grease into the gap between the sleeve and the swing arm frame which then enters the swirl groove. Like 5twins just said above if you have a lathe you can do more refinements and if you do not then drilling could be all you need to do.

    I do have a small lathe so I now have limitless refinements to indulge in!
     
    Last edited: Jul 21, 2018
  19. 5twins

    5twins XS650 Guru Top Contributor

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    I should also mention that even though the original grease nipples may not seem needed after you add a new one to the center of the arm, it's still a good idea to keep them and give them an occasional shot of grease. That will keep the area between the pivot bolt and sleeve "wet" with grease. There's no movement there (or shouldn't be) but it will keep the 2 parts from rusting and seizing together. You'll find numerous threads about the problems folks have had getting these things apart because they weren't greased and got rusted together.
     
  20. Jim

    Jim The thrill of victory and da agony of da feet. Top Contributor XS650.com Supporter

    Yeah, but for those that do.... it's another option.
     

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