Join Date: Jun 2003
Location: Montreal, QC, Canada
Replaced the radiator cap and hasn't happened since.
The old cap did not have any visible defects though.
Forgot to mention the burping was coming from the reservoir overflow tube.
These symptoms are fairly common with time / age on the K1200RS/LT , it clearly means the radiator cap is/was defective.
By design, the K1200RS/LT have higher pressure rating radiator cap (21 PSI / 1.5 bar) compare to most Japanese water-cooled motorcycles (16 to 18 PSI). This value of 1.5 is stamped on top of the cap, so make sure this is what you are being offered as a replacement.
ANOTHER IMPORTANT POINT: although the expansion tank (under seat) has a MAX mark, I would suggest to only fill about 1/4 inch above MIN when ENGINE IS COLD and no more. The size of the tank combined with coolant expansion is such that it will overflow when HOT if you use the MAX level. I have tested this on many K1200RS in good mechanical shape with same result...
John (Montreal, CANADA)
K1200RS (2002 IceBlue/Red - 96,000 miles)
Last edited by sailor; Oct 4th, 2019 at 7:04 am.