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wave washer mystery solved?


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Re: 97 R1100Rt trans trouble post below.


David said:That is the wave washer on the input shaft. Here is the one that came out of my tranny. In January 2003, Gina's in Iowa City charged about $1200 to remove the tranny, replace the wave washer, replace all the bearings with the updated "clean" bearings, replace the rear input seal, and do a few other things.


I also, found a large piece of a wave washer in my transmission. It is not shown on the fiche.


I sent an email to Tom Cutter and he said he had encountered it as well, via an enquiry from Florida, but could not say how to get a replacement.


I called Bruno at lunch today and had a great chat. He suggested it was the steel part of the rubber seal on the clean bearing that failed. It made sense. I pulled the bad bearing after work and as the attached pics show: he appears to be correct.


The only question unanswered: What did Gina's put in David's transmission?


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Not so fast. Gina's was quite clear that it was a washer that was broken in my transmission, not a part of a bearing. I trust them to know what they were looking at when they called with the input shaft in hand. I have the whole washer, and it is plainly a wave washer. If it is a broken part of a bearing that just so happened to get formed into the perfect potato-chip shape of a wave washer, it's a miracle right up there with finding Jebus on your grilled cheese sandwich.


What they put in was:


07119963200 x 2









21211242377 x 6

21211454417 x 6






Most of which is replacing the high-mileage original bearings with sealed bearings.

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This is the input shaft that came out of my bike. It looks like there's a wave washer as part of the cush drive, which is probably sold (to us, at least) as an assembly.


Is this what you guys are talking about?





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Here's the parts fiche for the input shaft of an M93/94 transmission:




It looks to me like there's something missing in the fiche - where's the part that in the photo is immediately to the right of the spring? Unless it's part of the machined part of the input shaft, which I doubt. Part # 3 is a part that was replaced in my tranny, but it's a 28 x 44 x 3 washer, which the broken part that came out wasn't. The Compression Spring and Thrust Adapter, they didn't replace (or didn't charge me for).


Whatever that wave washer is, it sure looks like it in the second photo. Flipping Bart's photos around to match the parts fiche:







it sure looks like the wave washer in there. But I can't make sense of what's what, looking at the sizes of the various washers and spacers and trying to match them to what's next to what in the photos.

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It sure doesn't look like the fiche is describing the same part as in the picture... but are we sure that the input shaft in the photo is from a M95/95 transmission? It looks like it might have come from a M97 (or at least a time in the M95-M97 evolution where it was mostly a M97.)

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My bike is a 2000, so definitely has the M97 tranny. When I did my input shaft replacement, I was unable to locate a part number for just the shaft on the various fiches for my bike, so ended up with the whole assembly (which is why I have this very expensive paperweight available for pics.)


Hot tip: five of the six bearings in the tranny--all but the big one on the back end of the intermediate shaft--were available and in-stock at my local bearing supply house for WAY less money than from BMW. The guys at Gopher Bearing also assured me that the Brit-made bearings they sold me were at least as good quality as the Japanese ones BMW uses...probably better.

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Exactly what we were talking about. Mine is an M97, just like the photo. My bad assumption was where the wave washer came from. It was farther down the shaft than I thought, which explains a lot as far as why the gear piled into the bearing enough times to wear the bearing inner race edge down enough to let the gear cut into the seal etc.


Now, I had the dimensions of the remains of my now verified existing wave washer and needed to find a reasonable replacement.


As an ex parts man, (Honda full line cars and bikes) I'm good at sourcing the unsourceable.


I found bmw p/n 23202 325 493 32 x 41 wave washer in the transmission of the R1200RT. Considering I almost put it back together with no wave washer, I'll take a chance on this one and report back on durability.


BIG thanks to All that posted here. I'll also get back to Tom and Bruno.

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From here and here:


Spring washers or wave washers are specifically designed to provide a compensating spring force and sustain a load or absorb shock.


Many design variations have evolved to best serve these basic functions.


Spring washers are typically used in applications where assemblies need a part to take up play, eliminate rattle, maintain assembly tension, compensate for expansion or contraction in materials after assembly, or to absorb intermittent shock loads and provide a controlled reaction under dynamic loads.


A Wave Washer is a flat spring designed to offer compression to remove rattle and take up tolerances. Wave washers are also referred to as spring washers. When wave washers are deflected, they exhibit uniform spring constants. Unless waves are equally distributed, the original deflection rate does not begin. The outside diameter is subjected to expansion and the inside diameter is subjected to contraction while loading the wave washer. Adequate space must be given for such changes. For effective performance of the wave washer, it can be designed in such a manner that the height doubles the deflection. Wave washers can be stacked by introducing flat washers in between.

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Thanks Dave, It'll be a topic at work tomorrow.

That also explains why there was one on a input shaft of a reducer I rebuilt several months ago.

If your lucky,you learn something new every day!!!

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