I got a non-running 91 k100 found a bad fuel pump. The engine turns over several spins then slows down like dead battery, new battery and same thing. Plugs out and spins great. Does this sound like a bad starter? Is this common? I have fire and new fuel pump ready to install.

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It's common for the starter motor to 'dust up' due to the brushes spreading carbon around the joint over time. It ought to be a maintenance item it's so common. It causes all manner of strange issues. If you're handy with a spanner and inclined to go have a look it might be worth yanking the starter out and disassembling it with an eye to cleaning it out with contact cleaner and/or replacing the starter brush pack.

The Google search engine in the forums two main pages will turn up heaps of info on how to extract the starter.

Cheers.

Sounds to me like the brushes are on their last legs. You can buy just a brush kit that has the plate included but before that check the earth connections at the gearbox just above the coils and the frame connection which is the engine mount bolt on the right just above and back from the alternator cover. Also the two bolts that hold the starter if there is corosion there its bad news.

Make sure you clean the fuel tank as we see many problems here because a new pump was installed and the tank not cleaned of the remainders of the dead vibration damper.

Pulled the starter today and opened it, found the bad brushes as was suggested. Thanks for the good advice.
Will try and find brushes on Monday.