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How Much Play is Acceptable in the Swing Arm?


jfremder

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I have noticed a tiny (less than .5mm, just barely perceptible) amount of play in what seems to be one of the swing arm bearings when I try to twist the rear wheel side-to-side on a verticle axis, holding it at the 9:00 and 3:00 position on the wheel. (Pushing one hand and pulling the other)There is NO play doing the same thing holding it at the 12:00 AND 6:00 positions. There is no play when pushing and pulling both hands simultaneously.

 

My '04 R1150Rt has just over 18,000 miles, and the swing arm bearings have never been adjusted.

 

I'm wondering if I should be concerned, and/or what course of action is called for.

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If the play is in the barely perceptible range I don't know that I'd really fret about it, but adjusting the bearings is a very easy job if you want to tackle it. You will need a few tools not normally found in a standard set, such as a 30mm socket and 12mm allen wrench, and a torque wrench. If you have access to these it's all of a 30-minute job.

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>>If the play is in the barely perceptible range I don't know that I'd really fret about it, but adjusting the bearings is a very easy job if you want to tackle it. You will need a few tools not normally found in a standard set, such as a 30mm socket and 12mm allen wrench, and a torque wrench. If you have access to these it's all of a 30-minute job. <<

 

I have those tools smile.gif Is the procedure in the shop manual?

 

I believe there are two bearings in the swing arm,and one in the hub. Which one needs adjusting?

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Yes, the procedure is in all of the R-bike manuals. The bearing set to adjust is the pivot point where the final drive unit connects to the swingarm. You can see the adjustment bolt with a hex head and the 30mm locknut on the (driver's) left side of the rear of the swingarm. I've never needed to adjust the front swingarm bearings and I doubt you will either, any play is usually developed in the rear set.

 

P.S. One tip... make sure you get all of the old Loctite crud out of the threads of the adjusting bolt and swingarm so you can get a good torque reading.

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Stan Walker

My 2 cents......

 

Buy new bearings.

 

I went the re-adjusting route a few years ago. It lasted about 20,000 miles before play started to appear again. This time I not only had to replace the bearings but also one of the pivot pins as the bearing was no longer rolling on it's balls, but was rotating on the pin itself.

 

Next time, if there is one, I'm going with the sleeve bearings that are sold as an after market item.

 

Stan

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If the play is at the 'swingarm to final drive' pivot. Check to make sure your adjmnt nut is not loose, it can happen. My pivot needed adjsmnt and I retorqued it to spec and 16,000 mile later I'm still good to go. thumbsup.gif

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Swing_Arm.jpg

 

The play seems to be in this bearing. Should I remove, clean, re-locktite, re-install and re-torque the fixed and floating bearing studs, or can I just loosen the locknut and retorque the floating stud?

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Should I remove, clean, re-locktite, re-install and re-torque the fixed and floating bearing studs, or can I just loosen the locknut and re-torque the floating stud?

Well how much of a perfectionist are you? The perfect solution is to replace the bearings. Play indicates they are worn, and officially there is no re-torque procedure/specification.

 

One step removed from that is to disassemble it so you can clean off all the existing locktite and get the most accurate re-torque.

 

Two steps removed from ideal would be to loosen the lock nut, heat the floating stud to soften the existing locktite and re-torque it from there.

 

Three steps away from perfection would be to forget you own a torque wrench and loose the lock nut, soften the locktite then just tighten the floating stud a 1/16th of a turn and see if that takes the play out.

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Play indicates they are worn
I don't think that's necessarily the case. The bike has 18k miles on it... simply retorque and go. I would fully expect to have to do this procedure every once in a while even on a bike with perfect bearings.

 

Simply remove the right-side bearing stud and locknut, clean 'em up, and reinstall/torque per instructions. Done.

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Play indicates they are worn
I don't think that's necessarily the case. The bike has 18k miles on it... simply retorque and go. I would fully expect to have to do this procedure every once in a while even on a bike with perfect bearings.

 

Simply remove the right-side bearing stud and locknut, clean 'em up, and reinstall/torque per instructions. Done.

OK, I'll bite... If the official spec. is no discernible play, and it is, and a correct bike exhibits none, and they don't; where did the play come from if not from wear?
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where did the play come from if not from wear?
I didn't say that none of the parts wear, only that some wear does not necessarily mandate replacement.
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Stan Walker

I didn't say that none of the parts wear, only that some wear does not necessarily mandate replacement.

 

Since the bearings don't actually rotate round and round, but just roll back and forth in the same little spot, wear tends to consists of digging holes in the race (the play that you now feel). Removing this play leaves the balls sitting in a low spot with no ability to move at all. Now the bearing acts as a single solid part and the movement of the swingarm is handled by the whole bearing rotating on the ungreased pivot pin. This wears the pivot pin, being softer than the bearing.

 

Buy the new bearings. Better yet, buy the after market sleeve bearings.

 

Stan

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They are actually lifetime oilite bronze bushings, not bearings. I bought two sets recently and put the first in Leslile's bike. She's really happy with the improvement in stability of the rear end, but I also replaced the crown bearing at the same time so I can't say it was just the bushings. smile.gif

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BucksTherapy
I didn't say that none of the parts wear, only that some wear does not necessarily mandate replacement.

 

Since the bearings don't actually rotate round and round, but just roll back and forth in the same little spot, wear tends to consists of digging holes in the race (the play that you now feel). Removing this play leaves the balls sitting in a low spot with no ability to move at all. Now the bearing acts as a single solid part and the movement of the swingarm is handled by the whole bearing rotating on the ungreased pivot pin. This wears the pivot pin, being softer than the bearing.

 

Buy the new bearings. Better yet, buy the after market sleeve bearings.

 

Stan

 

Does anyone have the BMW part numbers for these bearings?

I can't seem to find them in the parts diagrams.

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Joe Frickin' Friday
They are actually lifetime oilite bronze bushings, not bearings.

 

Do they bear directly against the surface of the pivot pins, or do you press one piece into the swingarm and another piece onto the pivot pin?

 

I've never had good luck with the stock needle bearings; I've replaced them a few times, and ended up with them getting sloppy within 25K miles. There's just too little movement during normal use, so they keep hammering the same locations over and over again.

 

Installed new FD about 25K miles ago. Haven't checked lately, but I'll bet the pivot bearings are smashed again. crazy.gif Will check in with the Rubber Chicken.

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They are actually lifetime oilite bronze bushings, not bearings.

 

Do they bear directly against the surface of the pivot pins, or do you press one piece into the swingarm and another piece onto the pivot pin?

It's the latter and it's a pretty slick set-up. cool.gif

 

He uses a timmken (sp?) race that you press into the FD and the oilite bronze part goes around the pin after it's inserted. You DO need to be careful that you don't have the bronze part inside the race when you whack on it as you're seating the race in the FD housing, since the bronze is so soft you'll mash it in short order! (DAMHIK!!) Best is to use a proper sized drift (or even a socket) as the outer edge you're whacking against (where the race tapers down) is pretty thin.

 

The bronze part should fit very snug on the pin and according to Tom, some 1150's are an even tighter fit. You might require some sanding with very fine grit (400) to allow the pin to pass through the bushing. After deforming mine, I had to do some serious repair work (I'm a novice wrench and have never done this kind of thing before). I went to Pep Boys and got a reamer for rebuilding brake master cylinders on cars that had two stones and which got down to the inner diameter of the bushing (which was 11/16ths IIRC). I stuck the reamer in my drill which I fixed in the drill-mounting chuck of my Zyliss shop vise, oiled the stones with some 3-in-1 and held the bushing with a gloved hand and worked it back and forth. I had the pin handy and took many passes with the reamer--regularly cleaning the stones of accumulated bronze, cleaning the bushing and testing the fit on the pin--stopping when I was just able to force the pin through the bushing.

 

Since the bushing goes inside the housing but the pin goes through from the outside, you need to put some grease on the race and the bushing to hold it in place for you to fit the FD and put the pins in to hold everything.

 

I bought a set for each of us and I still need to put mine in. I was planning on doing another illustrated walk-through when I do mine, but I don't know when that will be--probably after the UnRally.

 

[edited: bearing race goes in FD, not PL housing. dopeslap.gif ]

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If the play is in the barely perceptible range I don't know that I'd really fret about it, but adjusting the bearings is a very easy job if you want to tackle it. You will need a few tools not normally found in a standard set, such as a 30mm socket and 12mm allen wrench, and a torque wrench. If you have access to these it's all of a 30-minute job.

 

Last Summer I was pre-flighting the RT before a big ride to Canada. I thought I'd lube the driveshaft splines for good measure, didn't think it had ever been done. So I pulled the driveline apart and found, very much to my surprise, that three of the four bearings that hold the rear drive and swingarm together were TOTALLY blown!

 

57289476-M.jpg

 

57289480-L.jpg

 

They aren't supposed to look like that. I had never felt a wobble while riding, I had ZERO play in the rear drive or swingarm when I did the above-described twist and pull routine. It all started when I pulled the rubber boot between the rear drive unit and swingarm back. A bloop of oil drooled out and I found a teeny roller bearing in the oil.... Oh crap, what does this mean?? So I pulled everything apart and found the two swingarm-to-rear drive bearings totally shot and the right side swingarm-to-tranny case bearing shown above. I just about had the first Big One, thinking about what would have happened if I'd been cooking through a hard turn when all the rotten bearings finally let go....

 

Anyway, I ordered the replacements and bought the proper tools and the repair wasn't really all that difficult. You'll need a heat gun for removal of the stub axles because they're in there with Super LocTite that has to be heated up before it will let loose.

 

I put everything back together and took her for a test spin, all was great with the drive shaft and new bearings, but DAMN look what else decided to give!

 

57290166-M.jpg

 

57290114-M.jpg

 

It was now four days to departure on a 4000 mile ride, and so I freaked out and took her to the dealer for a crown seal and checkup (nerves were shot tongue.gif and time was gone). They replaced the crown seal and thoroughly checked everything else out (my bearing work was fine) and off we went! I've put about 10,000 miles on since then with ZERO issues.

 

So anyway, that's a very verbose way of saying "You should check it out as carefully as you can." I had no idea my RT had those bearing issues, and it wasn't all that big a deal to tear her down to that point and really inspect things. You can also get at the neutral switch, check the brake pads, etc. while in there! grin.giftongue.gif

 

I don't notice any handling difference with the new bearings, by the way!

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Hi Douglas!

 

Are you still running on the original crown bearing? Reason is you might want to check out this post and consider some more "simple" preventive maintenance if you're going to keep piling up all those miles on that bike so far from home! clap.gif

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