hello from the swamp! i just bought an 85 k100rs,a one owner bike with 32000 on the clock,and in excelent shape.i have only had it for a week and have already racked up 800 miles.what an awesom bike!i have owned other beems but this is my first k bike,do you guys know when my next major service should be done,and whats involved,and any info on using barbacks,or different bars would be welcome.the riding position is just a tad too racy for my old bones........

Welcome to our forum.

Not a lot of maintenance is required on these bikes.
What I would definitely look at is the splines. The grease "may" be old and the splines may be in need of lubrication.
As I also experienced, the grease on the triple tee may need to be replaced.
23 years old and so little mileage…. Some of the seals may have dried up. I would monitor the oil/water pump seal.
Check my page http://www.bmwons.ca/k100/k100.htm as I rebuilt a 1985 K100rt with about the same mileage.

Bert

now that you mention it,there is a little seepage under the pump.should i be concerned? there's no drips on the garage floor as of yet.is it a big job to rebuild?

as for the milage,thi bike has been ridden every sunday and kept in an air conditioned garage for the past 23 years.i think today might have even
been the first time its seen rain.all the visible rubber is like new

It could be tricky to install the new mechanical seal located between the 2 pumps. You need a press to push it in.
I always advise people to open their pump, clean it and have the dealer installing the seal.
You should check the shaft to see if it is worn where the seal rides on it.