I found this on the BMW k100 RT web page,
and its seems to suggest the bearing is lubricated by splash feed from oil dropping down onto the sump.
The engine lubrication system is a semi dry-sump type in which oil is contained in a reservoir formed by the crankcase lower section, thus minimizing the heat build-up and frictional losses that would result from major engine components running submerged in oil. The gear-type oil pump, mounted in a single assembly with the water pump and driven off the forward end of the engine output shaft; draws oil through a mesh filter set in the pick-up and forces it through a full-flow filter element into a main gallery. From here it is fed to the crankshaft main and big-end bearings and into the camshafts, which are hollow but plugged at their rear ends so that oil is positively supplied to all camshaft bearings and then out on to the lobes and cam followers; a supply is also taken from the camshaft gallery to operate the hydraulic cam chain tensioner. The teeth of the crankshaft/output shaft primary drive gears are lubricated by a supply passed through the output shaft itself. All other components are lubricated by splash, the surplus oil falling down into the crankcase lower section. Oil pressure is controlled by a plunger-type relief valve set in the pump housing and a bypass valve in the filter ensures that the oil supply is maintained even if the filter is clogged through neglect, to the point where it cannot pass sufficient oil for the engine's needs. If pressure difference exceeds the set amount, the bypass valve opens and allows unfiltered oil to circulate around the engine. A pressure switch set in the pump housing causes a warning lamp to light in the instrument panel if the oil pressure is dangerously low.
Does anyone else have any thoughts on this
bob