If the clutch is being let out and throttle used smoothly (without extreme throttle movement), whether at 1000rpm , 1500, 2000, 3000, 4000 ... the engine and power train are smoothly loaded. There's no absence of loading as the engine rpm happens to be at 2000 rpm or go through 2000 rpm. Of course, at any of those RPM's the clutch lever action can be too quick (not smooth), or the throttle can be opened too aggressively at too low of RPM, and you'll perhaps get some shudder or rattle from the sudden change in detonation, piston, drivetrain, or clutch change in acceleration as they adjust to a sudden torque change--but that isn't at ~2000 rpm alone. There's no reason why there's a problem at 2000 rpm that isn't there at 1000, 1500, etc.
My bet is that there's either something exterior to the engine/powertrain that is vibrating 'nicely' at ~2000 rpm (like a piece of faring or a bolt loose so a part isn't fastened) OR that the clutch/drivetrain has something going on mechanically.
Best advice is to get another ST1300 rider to swap bikes with you and both of you get a sense of the differences (if any) in each other's bike while doing the same thing that causes the rattle in yours at ~2000 rpm.
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[Tangential point... David, it is inappropriate to start 2 different threads on the same topic. Besides being bad forum etiquette, that is frustrating for those who are trying to follow and help with the issue.]
On the questions! I'm on here quite bit. I have learned so much from others members questions. There are some brilliant ST people on here that have helped us sort out issues and prevent problems occurring before they become an issue.
https://youtu.be/PJhnK4SOZlM
