Recall that a few weeks ago I had a 1988 K100 that stumbled intermittently. It never died. It just stumbled. Based on that I kinda went down the fuel path. I replaced the fuel filter and replaced the fuel pump with a IBMWR-suggested non-BMW pump, complete with the shimming required to have it fit.
It's quite possible that it only had some water in the tank. I don't think I know exactly what the original problem was, but it ran fine for a week or so and then it got worse.
Now it doesn't run above an idle. The link shows what it's like. It's an mp4 file.
I'm thinking of emptying the tank, putting the BMW fuel pump back in, and replacing the fuel filter again. The tank-to-fuel-rail line is relatively new. I haven't checked the fuel-rail-to-regulator line.
A brief peek in the tank today and the non-BMW fuel pump is still in place.
Ideas about how to diagnose why it won't run above an idle? I never put a fuel pressure gauge on the fuel line, so I don't know what pressure the system is producing.