My 85 k100RT recently began leaking trans oil at the rubber boot where the clutch rod exists the engine just in front of the rear tire. It leaked while it was parked (center-stand). I cleaned the area and checked the trans oil level. I did add trans oil about a month ago. What would cause a leak here. Also note that since finding the leak I have rode about 100 miles with no more leaks. What gives?

Hi Mike,
Is it possible you overfilled it? What oil did you top up with and what was in there previously? Could also be that something got under the seal lip which then leaked and was wiped away by the action of the rod operating.
Regards,
K-BIKE

I checked the oil level with the shock adjustment tool, but I did note that my shock tool has only 1 line on it, so I assumed that was the full line. It is possible that I overfilled it just a little. I checked it again today and still no significant leak, but the boot was damp with trans oil. I used Valvoline 80w-90, but I am not sure what was in it since I just got the bike in May and have not changed the trans oil. I believe it has been leaking for a fairly long period since there was a thick greasy buildup on the clutch arm, but the buildup was dry and crusty (sorta like grease buildup around a ball joint).

I would carefully remove the boot and inspect it.
This is a piece that can be easily cracked and oil will sip.
There is no seal on the clutch rod as the bearing is lubricated by the gear box oil.
Caution: Gently separate the clutch arm mechanism from the boot to avoid tearing the ruber apart.
A ruber boot cost approximatly $50

Hi Mike,
Excellent advice from Bert and good that you have checked the level best to eliminate all possible items. Have a look at the http://www.maxbmwmotorcycles.com/fiche/fiche.asp and put in your EXACT model and that will give you an opportunity to look at the exploded parts diagram.
Regards,
K-BIKE

Thanks guys, I think you have answered my question. If I understand correctly the boot is not just for keeping dust and dirt out, but is used as an oil seal. that being the case it probably has a small crack in it. When I cleaned it I probably repositioned the boot partially closing the crack. Thanks for your help
Mike