Big day today, with help from my pal Michael, who supplied the tools:
1) Compression check. Came up 150 PSI on cylinders 1, 2 and 4; 140 PSI on cylinder 3. Not bad!
2) Balanced the throttle bodies with a 4-channel Carbtune Pro. Thanks Duck as always for your great how-to.
3) New spark plugs. (This should be embarrassing -- I've ridden this bike over 13,000 miles in 20 months and never pulled the plugs. I have no idea how long they were in there before I bought it. Happily, all four had a healthy grayish tone, no signs of ill health. They were Champion RA6HC's; the new plugs are Bosch, from Beemer Boneyard.
Still to do: adjust the "choke" and the idle speed (balancing the TB's seems to have cooled down the idle).