I have a K100 4v, 1990. I wonder if I can inspect the clutch-disc, without unmounting the whole gearbox
If anyone have the knowhow, please tell me:lol:

HI there, the only thing I can think about is a optical fiber probe.
You could use the test hole at clutch´s housing bottom or the one existing at the top near the starter in some models.
But I don't know if this works.
Best regards
JAP

Hi, you can check if there is noticeable amount of oil near the hole under the clutch. If yes possible problem with seal and O ring between engine and clutch.
Check the position of adjusting screw on clutch arm infront of rear wheel. If that screw with counter nut is out too much clutch friction plate is at the end.
Drive the bike, for example, 50 kmh in 4. and hit the throttle, if rpm rise too fast, clutch is worn
Finally chech the whole asembley from stand position: if you feel vibrations at start probably whole clutch is ready for change.
Best regards