Hey guys,
just removed the transmission and clutch assembly on my 90/k75s. I swear, some people should never be allowed use tools. Whomever did the last clutch job on this bike is a moron, all 6 of the 6mm hex/allen bolts
were striped at the heads from over torquing, Moly 60 was slapped on so thickly on the output shaft splines that it has contaminated the friction/clutch plate. Where I live a friction plate goes for about $150.00
so I would like to save it if I can. Is it salvageable? It's thickness just over 5mm which is well within spec. and I haven't noticed any problems shifting with the clutch except the loud "clunks" during shifting that I thought were a BMW thing.
Thanks,
Chris

Hi Chris,
Probably the reason for the stripped out heads was the OAF (and yes I am shouting) used an Imperial Allen key which is close but just small enough to strip round the inside of the screw head GRRR!

Now if you have access to a vapour degreaser dunking the clutch disk in until it stops running, pulling it out to cool down and dunking it back in the vapour repeated a few times should leach the grease/oil out of the friction material and rinse away some of the MOS2.

Then you will need to lap the clutch disk friction material on some plate glass with 600 grit in water to grind off the surface with plenty of grit and water to remove the top few thou off the clutch material. and flush away. Dry with acetone and then back into the vapour bath.

I have resuscitated car clutches that way and had them work fine afterwards. The plate glass ensures they are all ground simultaneously and all flat in relation to each other. One caution do NOT use toughened glass use plain float glass.
Regards,
K-BIKE

I too have used the above method of removing grease/oil with a vapour bath and it does work, I have also used another method I was shown by a old boy many years ago and that was Sweating the oil/grease out of the contaminated clutch, okay it was on commercial clutch's this was done with a gentle use of a blow torch [not gas bottles] which raised the contaminating product's to the surface and evaporated them.

BIG D

The problem Chris has is he needs to do two things first is to remove the oil/grease from the clutch with either vapour bath and or sweating it out but then he has to get rid of the MOS2 paste much of which will remain. The only way to remove that is to grind that top few thou off and with it the dratted MOS2. That should leave clean fresh clutch material with lots of bite.
Regards,
K-BIKE

I didn't have access to a vapor bath so I used varsol and a wire brush to get the worst off then spray can brake cleaner and wire brush multiple times, torched with a propane torch, sanded it with 60 grit emery paper and finished off with spray can brake cleaner. It sure looks good, I'll find out in the spring. But as I mentioned even with caked on moly 60 the clutch was working fine, strange.
Thanks