Join Date: Jan 2009
Location: Mendocino, CA, USA
I had the same thing happen on my '93 1100RS. We found that if we simply flipped the rubber gasket in the cap over, that did the trick at least until I got home. Whether I replaced the whole cap or just got a new gasket, I don't recall, but never had the problem again. That would have been around 50,000 miles for that bike. My '00 K12RS never had the issue, don't recall if the cap was ever swapped out.
Specifically what was happening to mine, seems to be the same for you, was that it was fine while riding - this was a 1000 in a day ride - but at Every stop (Engine still hot but insufficient air flow to prevent expansion), it spewed out the rubber nipple on the overflow and had no ability to suck it back through the hose as it normally would. Once it cooled enough, no spewing problem until the next stop, the gasket simply was letting the no-longer cooled fluid past, similar to the pressure spring in the cap. Mind you, the temp guage would only approach the red once the bike stopped and spewing was going on. It never got higher than it would in stop and go traffic, and the fan did come on properly.
'00 K1200RS >135,000 mi, '09 K1300S sold @ 22,232 mi
'93 K1100RS traded up @ 78,000 mi, '85 K100RS sold @44,000 mi, Kawi 650 track bike - sold
Last edited by Y2K12RS; Sep 20th, 2010 at 6:39 pm.