My bike is a 1985 K100 with 76000km on the meter, so I think it's about time to change the camchain- tensionerblade plastic faces. A tricky job? Do I have to remove/dismantel the ignition trigger? Some advise please?

The ignition assy must be dismantled, to get the cover off (mark the position very exactly before dismantling).
After the cover is removed, run a zip tie under the chain above the chain tensioner, other end
around the above chain guide (to keep the chain from dropping down).
Remove the chain tensioner (watch out, it`s a spring inside), unclip the tensioner blade from
the bike, remove the plastic blade.

Mount the parts in reverse direction......turn the tensioner upside down to get the internals out,
compress the spring and piston and put it back in the tensioner housing in this state.
Keep the tensioner compressed, mount the left/down screw finger tight, swing the tensioner up to the
blade, mount the last screw.

An other story is that if it`s needed yet? I know BMW recommend this at 60K intervals.
I can mention that I did this work for the first time (together with the chain) at 190K on my bike, then it was worn 1,1mm into the plastic (total thickness 2,5mm).
But of course age also must be put in as an factor, my bike was 12 years old at that time.

Good luck!!

Inge K.

May be it can wait another year or two. I'm checking the valve clearance, and thought I could do the job while I'm waiting for some new shims. (the parts are in my shelf allready, was orderer when the bike passed 65000km). Thank for your reply