Spline Lube Musings...

[Justin B.]

I have been wondering about various conventional spline lube procedures for a while and have had a wild thought.  It seems to me the primary purposes of lubing the splines is to reduce wear between the input shaft and clutch disc and provide smooth sliding between the two components.  Secondary purpose would be to maybe provide some corrosion protection.  

I have a thought for those of us that live in climates where the rust/corrosion issue might not be a problem - Coat the input shaft splines and inside splines with one of the dry-moly products.  We use an aerosol applied moly lube at work that is sprayed on and when it dries all that is left is a coating of the compound which is not wet or gummy.  

Seems to me that this would provide the proper wear resistance/lubricating properties desired without the side issues of attracting dirt and gunk and spitting grease all over due to overzealous application.

Any thoughts from the collective on this?

[Bob_Roller]

At work, we have a product called GN spray, it's an aerosol can of a moly based dry lube, the volatile part evaporates in a few minutes, whats left is a gray/black residue .

Only problem with it, is that on a sliding joint, it comes off fairly quickly .

I've been thinking about alternatives as well, haven't come up with anything suitable yet .

[montmil]

As the ill-designed and sorta-exposed input/clutch splines for the dry, automotive-type clutch can't be lubricated via the BMW's rather primitive oiling system, I kinda think some sort of grease would be required to keep the sliding and rotating spline teeth rust free and adequately lubricated.

It would certainly be nice to just hit the splines with a little rattle can spritz once in awhile.

Monte

[nhmaf]

Paul Glaves, and other airhead illuminati all claim that the paste/dry moly compounds often aren't sticky enough on their own to stay put, and that the gooey-er tack greases aid as an "adhesive" of sorts, along with providing a better film barrier to corrosion protection.   It isn't very salty where I am, but it sure does get wet (and if one rides in the winter/early spring, the roads are COVERED in salt), so I think that there is some merit to their claim.

Having said this,  I have used straight-up Moly-60 for spline lubes in the paste, but am now starting to mix it with some "red-n-tacky" heavy duty grease on spline lubes both on the bikes and on the tractor...

[Johnster]

In my time on a nuclear submarine, we had "colloidal graphite" IIRC - it was graphite powder diluted in alcohol - sounds like it worked jsut as described above.  It was the **only** lubricant allowed on many of the nuclear-sensitive valves.

However, those valves were not subject to the same kinds of forces as an airhead clutch.  And clutches get moved a lot more than these valves did...I can see the clutch wearing the graphite right off of the splines and they'd be effectively naked in the first few strokes.

yeah, I coulda worded that better..oh well =)

-John

[MrRiden]

This poverty rider has used the grease that is sold in little packets at AutoZone meant for lubing the pins that floating brake calipers slide on. I figured it was high temperature, meant to stay in place and designed for load bearing bits. Cheap, proper amount and so far no complaints. Probably not used on nuclear subs or space shuttles but when your cheap like me it's a gem! I do have some rattle can white grease but it drys out fast even on the garage door bits.

[bjamesw]

BMW Lubricant #10.  
Part no. 95 00 9 000 190

It was there on the shelf when I picked up my trans after getting the input shaft replaced, the mechanic recommended it, it's listed for this use in at least  one of the service manuals I checked, and it was suprisingly inexpensive.  I don't know what it is now but it was like six bucks for a 238.5gm tube.   About every 15000 miles I back the transmission and swingarm back,  clean the splines as best I can,  pack a little into the splines and bolt everything back together.    At first I was really really pissed that BMW required me to do this crap to a design that (it was hoped) would win a war in the mud trenches of Europe, but the third time I did it only took me about an hour.

What is in the new(er) bikes?   How did they remedy this?  Or do the new bikes have wet clutches?   I've sometimes wondered if a little rubber bellows could be mounted here to keep moisture and elements out.  That would have been nice.   Or even a very small hole drilled through the input shaft at a point that was always covered by the female clutch splines.  That hole could be packed with a very very heavy heat stable grease that would migrate centrifugally out of the hole tiny bits at a time over the course of 60K miles or so.  

[Bob_Roller]

The F series bikes have multi plate wet clutches .

To the best of my knowledge, the R and K series bikes still have the single plate clutch .

I got a small tube of lubricant from BMW specifically for clutch splines, I think the printing on the tube is Microlube GL261 .

Very sticky grease .

A bit costly, $18US for about a one ounce tube .

Was highly recommended by the independent BMW shop I do business with  .