There are several checks and maintenance proceedures in the area of the rear wheel that should be performed regularly for your ST to give you all of the maximum trouble free miles it is capable of. A convienient time to do this is when the rear wheel is off for a tire change. Take a few extra minutes to do the following and help keep your ST in top shape for many trouble free miles. Use the Service Manual for a detailed step-by-step proceedure to items below.
While the rear is off make sure to inspect the two o-rings. One is easy to see on the splined part of the final drive flange (the 5 stud thingie that slides into the damper assy in the wheel). The other o-ring is under the final drive flange on the rear wheel hub itself. This o-ring is sometimes overlooked and often times not readily visible, as it may have turned to dust) it is a 61X2 mm part # 91302-MA6-003. Also check the condition of the rubber dampers and their respective metal inserts. There are 5 of these, and are accessed by removing the damper holder plate (5 socket head screws) Look for slop and also check for any wear marks on the wheel hub itself. Replace all of these dampers if excess slop or wear on the hub is found.
Upon assembly, lube the thrust washer under the final driven flange, the flange mating surface and the hub mating surface, and the splines on the outside of the final driven flange with molybdenum disulfide paste. Then, with the final driven flange inserted into the damper assy in the wheel (and new Excedra mounted and balanced ), apply NLGI #2 grease to the driven flange splines and ring gear engagement splines (final gear case). While your at it, check the rear brake pads for wear and contamination, clean up any corosion and road gunk on the caliper, rear axel, rear caliper stopper pin bolt, caliper slide pins, and piston. Check the caliper piston for brake fluid leakage and R&R the piston and seal (see: http://st1100.org/howto.cgi?job=HOWLONE&id=40 for more info) as needed. Then LIGHTLY lube the axel, rear caliper stopper pin bolt, and caliper slide pins with anti-sieze and assemble. Insure that the caliper slides freely on its pins and there is no binding.
You may as well take a look at the rear shock for tightness of the mounting bolts and any leakage. While you're there, check the exhaust system for tightness and obvious damage.