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Dangerous Bar Backs!!


drharveys

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I've had a bad experience with some potentially dangerous bar backs. When I executed a sudden swerve, they slipped! Try holding up a liter plus bike with flopping clip-ons! The bike went over, fortunately it was at a stoplight, so aside from a scrape on the left valve cover, nothing was damaged except my pride. Had this happened during, say, an evasive move on the road, the consequences could have easily been much worse.

 

These are the bar backs that came with my R1150RS. They were installed by the dealer, and were on the bike before I even test rode it. I don't know who the manufacturer is, and since our St. Louis dealer has gone belly-up, I can't find out. So if you have, or are thinking about, bar backs for your bike you should check this out. They may be deadly!

 

cda71232.jpg

 

The one on the left, with the bolt in it, is upside down. It is the surface which mates with the attachment point on the bike. You can see the obvious wear. The one on the right shows the top surface which mates with the bottom of the clip-on type handlebar. There is no wear on that surface.

 

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This photo shows the attachment point on the bike. You can see the wear on the mating surface corresponding to the bar back's.

 

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Now here's the mating surface on the clip-on handlebar. Notice that it has a lug which fits into the slot on the bar back or the bike. Also notice that there is no wear on it's surface. That's because it was mated to the top of the bar back. The bottom of the bar back has no lug, and that's the surface with the wear!

 

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And, to add insult to (almost) injury, here's the bolts. The one on the left was from the bar back, on the right, BMW's bolt for the clip-on. So not only was the bar back lacking the lug, it had a significantly shorter bolt.

 

DSC01247.jpg

 

And here's everything back together WITHOUT the bar backs! Torqued down to specs, with a dab of blue locktite on the threads!

 

Needless to say, I'm not nearly as sympathetic towards the loss of our local dealer.

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ShovelStrokeEd

Looks to me like an isntallation error, not the fault of the barback. It appears the installer got one of them tooth to tooth and used the wrong bolt. One can only hope that the mechanic who did the job didn't find another in the motorcycle industry.

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Looks to me like an isntallation error, not the fault of the barback. It appears the installer got one of them tooth to tooth and used the wrong bolt. One can only hope that the mechanic who did the job didn't find another in the motorcycle industry.

 

The installer didn't get ONE of them wrong -- the failure was bilateral. The failure didn't occur right away, it developed during my first year of ownership of a new bike.

 

Both the left and right sides showed similar wear. Quite simply, long bolt joints with lug: no wear, no slippage. Short bolt joints without lug: failure!

 

Having the lug fit into the groove prevented the vibration and micromovement that permitted the wear and eventual failure. I don't think the mechanic pulled the bolts out of his parts bin, they most likely came with the bar backs.

 

As for not matching tooth to groove, had that been the case, the failure would have occurred much sooner, probably the first time I braked hard. Besides, the bolt going into the bar back, just like the one on the BMW installation, is at an angle to the joint. That's so that as it is tightened, there is also a component to the force which forces the serrations to mate.

 

There is also a much more solid "feel" to the handlebars now. Yes, there's an anti-vibration mounting, but the whole thing just feels more "solid" now.

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ShovelStrokeEd

I'm not going to argue with you.

 

However, bolt engagement, if it is at least one and a half diameters, should have been sufficient. Perhaps it was never properly torqued. When did you check the bolts for tightness? I have seen similar installations and no one has reported a problem.

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Those are the factory adjustable handlebar pieces used on the K-RS (and the R-RS?). Been in use successfully on 1000s of bikes. If yours failed, I'd also have to point toward an installation error.

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i had those on an 1100rs i used to have. once in a while, one side or the other would start to get a little loose. it was extra hard to tell because the bars were rubber-mounted. i kept the correct sized wrench in my tank bag at all times. at random stops i would check them just in case. it never got so loose as to be a major problem in my 3 years of ownership, but it made you think.

good luck and keep that wrench with you.

 

tom collins

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Don_Eilenberger

The installer didn't get ONE of them wrong -- the failure was bilateral. The failure didn't occur right away, it developed during my first year of ownership of a new bike.

 

Both the left and right sides showed similar wear. Quite simply, long bolt joints with lug: no wear, no slippage. Short bolt joints without lug: failure!

 

The purpose of the lug to me seems fairly obvious - and perhaps others are missing it. It keeps rotational forces away from the teeth on the barback. I suspect BMW put it there for a reason, and probably with some experience with the teeth wearing due to rotational movement.

 

I agree - the barback does look like a potential problem spot without the lug - but using a bolt with some loctite should prevent the type of failure you had. That sort of failure - without the bolt being loose - would require sheering off of the teeth, and I don't see that happening if the bolt is kept tight.

 

Good design - no, probably adequate with correct installation and maintenance.

 

The shorter bolt may be due to the barback having less depth to it than the actual bar mounts on the bike, and too long a bolt may bottom out in the grip mount causing exactly the problem you're trying to avoid.

 

I wouldn't condemn the design - but I'd advise some caution if you're using it to check that the bolts ARE tight.

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Don_Eilenberger

One additional note.. in image: http://i40.photobucket.com/albums/e204/drharveys/1e76e2e9.jpg

 

It appears that the barback section without the lugs was actually fastened at the furthest back position on the mounting on the bike. Doing so means the teeth would have been down in the part of the casting without teeth... This is bad since then full engagement of the teeth isn't happening. The factory design with lugs prevents this from happening - since the lugs limit where the two parts can be engaged.

 

THAT is a bad flaw in the design, and again - something people should check. I suspect that a flawed installation was the cause of your problem, combined with a not fully thought through design.

 

YMMV and all that..

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I installed a set of these on my 02 RS and the hardware ( bolts ) are the same as what I used. The barbacks come with 2 bolts and if memory serves me correct, the BMW bolt was longer due to the thickness of the mount it passed thru was much thicker than the new bar mount, hence the shorter bolt attaching the handlebar to the barback . I would suspect that they managed over time to work a little, and I mean a little , loose. The instructions made no mention of using Loctite. I agree with the above about not being able to notice it with the rubber mounts. And the quality of aluminum used in the BMW part was probably better than that used in the barback, therefore it was in better shape. I do remember that though they look real easy to install, for some reason they were kind of a bitch to do. I also think that there were some design issues as well. On the early RS's it was possible not not only to change the front to back adjustability, but you could also change the angle of the handlebar as well. They did away with this when the 1150 came out and I wonder if they felt thay had too many ways for something this important to work it's way loose. As for the manufacturer of yours, because they were powdercoated black, I think those were Touratech...mine came from Bob's and were just plain aluminum.

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I have had bar backs for years on my 1150 RS with no problems. I see that your photos show a "taper" to them. I'm not familair with that brand either. Mine are not tapered and are very solidly in place. Could be the torch was set improperly or, the bike's bars had impacted the road and were not checked before you purchased it.

John

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Thanks to everyone for their opinions and experiences. As for me, the bar backs are now aluminum fishing weights. Since I have learned (also at least in part from this board) the correct posture for riding a sport tourer -- bend at the hips, back straight to slightly arched, no slouching and no weight on your hands -- I don't need them, and the bike makes me happier without them.

 

So now the only non-BMW items on the bike are my Air Force sticker, the BMW Motorcycle Owners of Japan dash plaque, the Sargent seat and the NOS sticker!

 

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I've installed two (2) sets of these critters on two (2) different RS's and have had absolutely no problem whatsoever with either of them. And the bikes aren't ridden at a liesurely pace either. At one point, due to necessity, I even had to trailer one of the RS's and the only option for tying it down was by the ends of the handle bars! No problems but would definitly not recommend this to anyone. But in any case, they held. I'm sure that I'm not the only person that has not had problems with this design so I would definitely have to point a finger at the installer. A little bit of blue locktite, as is recommended in the instructions goes a long way. Also, a periodic check of ALL of the fasteners on your bike would be a good practice to adopt. Just because it's BMW doesn't mean it won't come plum untight!!!!

 

Love the color of your RS, it's not as fast as my red one but it's still pretty!

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