Originally Posted by H96669
I'll ask first...are both the ground cables connected???Everytime someone comes up with some hotstart issue they seem to have missed connecting one of them cables.
As for the overheating, them bikes should run at 1/8" below the middle mark in normal highway conditions and that includes temps in/around 100F. Anything above that and suspect plugged radiators. Mine was running at the middle mark the first summer, rads were 20% plugged with road tar, bug crap and sand.
Fluhsing in place may help but in my case I had to remove the rads for a good cleaning.
In addition to these good tips from Pierre:
(1) By design, the K1200 is running a medium-high pressure radiator cap (1.5) in order to increase boiling point and efficiency.
(2) Above point implies that to function properly, no air should be present and circuit (both rad) must be completely full when cold. You will never achieve higher pressure inside with too much air in system.
(3) In order to reach full level on both rad, you need to have bike parked level on center-stand, engine completely cold, and fill from cap on left rad. In many cases, you may get better results by having the bike leaned slightly to the right to force fluid to go to TOP of the opposite rad.
Flushing and filling does not NEED a special tool on these engine (not like the new slant-4 K bikes from 2005). But you may need to do 1 ride (or warm up until fans starts) without left fairing - then let it cool down and add some more if needed (trapped air).
After many tests, I do NOT believe in just adding to expansion tank (under seat) and assume that the radiator level will adjust itself from that fluid. Also, once you are done (including 1 heat cycle), do not fill expansion tank on MAX level when cold as it may overflow when hot. Leave it between MIN and MAX when engine is cold.
*** Get a CLYMER shop manual and you will have a lot of info on the K1200. Very cheap (about $40 on Amazon) for everything you will learn. For 95% of repair and maintenance, the CLYMER is better with more pictures than the BMW shop manual (I have both).