As a long time airhead owner I know nothing about the flying bricks other that they have a stellar reputation for reliability. I plan to have a summer fling with one next year and then see where that leads. Winter is the time to buy, so I am looking.
The K1200GT is one that I covet, but the black and silver K1100RS SE is uncommonly attractive.
What should I look for when buying used? Is there any indicator about known weak points such as fuel pump? I know about heat from the K11. Are there other annoyances that could sway the decision? What about ease of maintenance? I do the standard maintenance on the airhead and it runs well.
On the Road
I have a 95 K1100RS owned it since 1997. You will notice more heat on the K bike because you are sitting behind the radiator. All water cooled bikes dump heat on the rider. The K1100RS will put a noticeable amount of heat on your left ankle, wear the proper riding boots and it wont't be a problem. The fuel pumps on the K are no less reliable than other BMWs. If the bike sits for years the fuel pump can be a problem along with the rubber damper it is mounted in. The K bikes take less maintenance then an airhead. If you like to adjust valves you will be disappointed with a K bike: the valves rarely require adjustment. Clutch splines need to be lubed at 40000K on later K1100 bikes. Renew the Clutch shaft o-ring at that time and you will eliminate the most common oil leak problem. If you buy a K bike learn how to read the engine fault codes. There is allot of info out there on how read fault codes, most of it is correct. Some K bikes take oil, some do not, mine does.
Bob, I own a '96 KRS with 100K+ on the clock (all mine). My three long standing gripes against the machine are oil consumption, lack of a sixth gear and excessive heat. The first two I cannot control. The third can be mitigated though not eliminated. That being said there isn't anything out there new or used that I would trade it for.