Hi,
As the previous clutch plate was not properly installed/aligned on my 1985 k100rs it ruined the gearbox input shaft teeth.  I replaced clutch-plate and gearbox with an used one and greased it with Staburags NBU 30 PTM , not to much not to little… After 2000 km/1250 miles I had again problems with downshifting. I was afraid there is again a clutch problem ! And yes all the Staburag had become a dry brown powder by the clutchplate/gearbox. See images. ( Luckily no damage to the teeth of clutch plate and gear box.)
I used the same Staburag on the cardan when I had installed the other clutchplate and gearbox. On the cardan all was looking good as I was thinking maybe the Staburag grease is fake. Checked where I bought it - an official bmw dealer. Real Staburag NBU 30 PTM !  I talked to some mechanics around here and they suggested heat did make the Staburag to powder.
Although you see some of the brown powder I have no slipping clutch. Clutch cable play is also good. There was also no burn smell when removing the gearbox. All looked clean and normal on the inside of the clutch housing. Gearbox also no problem. No clucks clinks when shifting and resistance when rotating with my hand. Greased again and put it all together  Down shifting is smooth again.
How can there be an overheating by the clutch/gearbox ? I am just worried that 2000 km/1250 miles later I am back to the same problem. Has anybody an idea why the Staburag went to powder ?  Thanks for your suggestion.

Images
https://i.servimg.com/u/f39/20/23/00/85/img_2014.jpg
https://i.servimg.com/u/f39/20/23/00/85/img_2013.jpg
https://i.servimg.com/u/f39/20/23/00/85/img_2015.jpg

Never had that, never met that....

Staburags should handle also heat.

I guess what was on your splines, is not Staburags, or it has seen something before.

Staburags NBU 4 is beige colored; NBU 12 is brown.

Staburag NPU 30 PTM is light grey.

I was thinking maybe the Staburag I bought is fake. Checked where I bought it - an reputable bmw part seller. (De Hobbyist in The Netherlands) Real Staburag NBU 30 PTM from BMW !

I used the same Staburag on the cardan when I replaced clutchplate and gearbox. On the cardan all was looking good.

So yes I am very confused why at the clutch the Staburag 30 went to a rust brown colored dust.

Been there last week (for other parts).
Do NOT order imitation valvecover seals for K75 there, they don't fit.

But sounds good.
Did you clean the splines of the gearbox first? Brake cleaner is your product to go on that.

What is the color of your Staburag 30 when you put it on the splines.  Is it starting out grey or brown?  Like the others above, I have never heard of it changing color.

Arlina, thanks for the brake cleaner tip!  I'll bet it makes cleaning the splines a lot easier.  Will have to remember it the next time I'm doing splines.

It is light grey, straight from the tube, when I put it on. ( Use a toothbrush as Chris Harris suggest in his youtube video. )

The same staburag 30 grease I used at the same time to grease the splines at the drive shaft. Only at the clutch/gearbox splines it became rusty looking powder after just 2000km.

I did not use brake cleaner - good tip ! - thanks Arlina. There was just the brown 'staurag' dust and brushed it all off with a toothbrush and checked the grooves with a magnifier glass and pincette or there was maybe still dirt.

Many moons ago chief Fat Slider told me, if you add new grease, remove the old one first.
I took notes and painted it in a cave. Researchers still puzzling it out today  
Lucky me in this modern world there are cheap spraycans with brake cleaner, and some single-use brushes (wich can be cleaned with the same spray).

Arlina wrote:Many moons ago chief Fat Slider told me, if you add new grease, remove the old one first.
I took notes and painted it in a cave. Researchers still puzzling it out today  

I wonder if the scribblings are still there in that cave? K bikes have been around for a very, very long time.

I contacted Kluber the maker of the staturag -  this is there reply.

What we are seeing in the photo is not the grease turning red. That is actually the by-products of wear between the spline in the clutch hub and the output shaft spline, which then oxidizes and turns into rust power. This typically occurs when there is insufficient lubrication, or when the lubricant has "worn out" due to time and exposure to heat and shear. Due to the age of the grease tube you have, which is over 6 years old, this grease has expired. The shelf life for this grease in an unopened container kept in a steady climate of room temperature is 5 years.

It is very probable that the grease had separated prior to you applying it again in 2018 and therefore, not all the ingredients were together when you applied it onto your clutch spline.

In any case I would recommend that you discard that tube and get another one. Even better, I would recommend you procure a 40g tube of our Microlube GL 261 over the Staburags NBU 30 PTM. The Microlube GL 261 is our recommended grease for spline to spline connections like this. If your dealer does not have the Microlube GL 261, you can ask them for the Steering cone grease Klüberplex BEM 34-132 and use that instead as it is a better grease for this application. The Staburags NBU 30 PTM, really is a type of assembly paste.

Make sure to thoroughly clean the rust off the splines and clean any other residues before applying the new grease. The use of a Scotch-Brite pad and a soft  bristle implement like an old toothbrush works great. You can use a tiny little bit of mineral spirits on a rag to wipe the splines clean when you are done, but make sure they are thoroughly clean and dry before applying the new grease.


---  Tube was 4 years old in 2018, within there 5 year.... Tube was stored closed without an air space in a cool near constant temperature. I did not see any separation. Even now, 6 years from buying, no separation to see. Also I did not find that there was wear to the splines. No shininess on the teeth, the powder, although dry, still worked as a grease barrier on the teeth.