Service Bulletin but not for the RS?

[Grumpy Goat]

Last night Wayne asked for some photos.  l sent him some so he will likely post those.  One shows me squeezing the duck bill and it opening so water should come out if there is any or enough to force it open.  I can also grab the duck bill with my finger and thumb pushing the duck bill up and down so not tightly fitted in the hole.
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Darrell's photos are below. 

I have actually done a shaft service on this bike (videos are on my YouTube channel) in addition to looking at countless videos on the subject. To say I am skeptical that this duck bill valve sill solve anything at all, is an understatement. We need to step back a bit and look at the issue ... what is the evacuation of moisture supposed to do? Reduce moisture content inside of the cardan shaft housing, and hence mitigate the conditions required for corrosion in way of splines that are not well lubricated. However, both ends of the cardan shaft housing also have rubber boots which are not watertight. The aft boot is shown below. Both boots have rubber clips (4 off) which clip to the cardan shaft housing and a sealing adhesive is supposed to be smeared at the clip interface between the boot and the housing.

   

This adhesive seal may or may not be there and even if there, there is no guarantee that it forms a complete seal. Point is, moisture will seek the least difficult way to get in / out of the shaft housing and my guess is that it will leak out and in at the boot-housing interface, while bypassing the duck-bill [one-way] valve entirely.

Speaking of the duck bill valve - how is entrained water supposed to get out? What is the pressure needed to push past the slot opening of the valve, when there is atmospheric pressure either side? Meanwhile the boots allow free communication.

But then what is a little rust between friends, right? I mean what is the problem with the shafts anyway? Is it the rust? Or is it the failure of the universal joint itself? The rust is superficial and causes a PITA when time comes to drop the final drive (see my video on this) but does it really cause failure of the universal joint? I argue that it has zero effect on the failure of these joints, and these failures come because of repeated cyclic / impact loads at the joints. Having nice lubricated splines mean that the cardan shaft is easy to come out if/when needed. The lubrication is also good at any gear interface for smoother quieter cooler operation.

The reason why you want the splines to be rust free is so that the shaft can be removed for inspection and hopefully replacement before they fail on the road, an inspection that still may not be called-for in the maintenance schedule of these bikes - someone with a 2022 can comment on this.

Until and unless they make the universal joint stronger (how strong?) they will continue to fail despite the band-aid rust-reduction solution that the likely useless duck-bill valve will provide.

My 2 cents.

Meanwhile I have bought a clip for the front spline and will continue to pull my shafts every 12k miles so I can inspect the joints either end.

Darrell's photos