Having read this thread, I checked my LT hoses (on a hot(tish) day, bike on side stand) and was equally surprised that the bottom hose was all sucked in. As with Snod Blatter's, everything else appeared normal and the expansion tank level was where it should be.
Then rode into London yesterday and near disaster! After a nice steady run for the first 110 miles, cranking along at max road speed I then hit the London traffic - 3 lanes of closely packed vehicles without enough room to squeeze through and all crawling painfully slowly along. Very quickly I noticed that my temperature gauge was rising and then realised there was no reassuring roar of the fan cutting in. Temperature quickly in the red and as the traffic wasn't really stopping, no chance to kill the engine when stationary. Interesting the high temp light never came on on the dash (I was waiting for this as my cue to pull over urgently). Next thing I was in a cloud of steam as the system boiled over. Made a quick exit off the road and up onto the pavement (sidewalk) and shut down. Expansion tank was empty, hot fluorescent coolant was dribbling everywhere.
Having allowed the bike to cool a little, I managed to roll back down the pavement and cut into a side road that was clear of traffic. Located a service station nearby (thank goodness for GPS) and managed to ride there to buy some more coolant to refill the expansion tank. Even with the coolant lost, provided I kept moving, the engine temperature stayed normal, but as soon as I had to stop (traffic lights etc.) the temp gauge would immediately start rising. Eventually made it to my destination in North London, 10 miles further on, where the bike was able to sit and cool properly while I socialised and drank coffee/ate cake.
I topped the expansion tank up a couple of hours later before heading off to see my sister to the south of London. What a nightmare journey that was - riding right through the centre of London in heavy traffic on a Saturday, red traffic lights every few yards. I certainly didn't enjoy the sights, loads of roads were shut off for some unknown reason (particularly around Trafalgar Square) and the GPS was being difficult (kept losing signal - probably due to the lack of clear sky between the buildings). To add to the misery, I had to endure torrential rain (it is Wimbledon and Glastonbury week - so what did I expect from the British weather), but at least that added some external cooling to the engine block! I was relieved to finally get to my sisters, but provided I stopped the engine every time I came to a standstill, the temperature remained OK for the journey (nearly 2 hours to do 22 miles!). Hate to think how many start cycles I put on the starter/battery!
When I arrived, I noted the bottom hose was sucked in but the expansion tank level was half a glass. This morning (I was persuaded to stay over for supper a couple of glasses of wine and a bed for the night - didn't take much persuading), I noted the hose was back to normal, but the expansion tank was empty. Topped up to max and rode home without any problems and no traffic delays, but now the expansion tank is back the the half glass level.
Now to tear down the bike and get the fan working again (it work beautifully in Dublin traffic a couple of months back), restore the coolant level (I don't have any leaks, so think the emptying expansion tank is just it doing its job of topping up the radiator every now and then), and most importantly dry out/flush all the wiring under the fuel tank out with WD40 electrical contact cleaner - I haven't looked yet, but I am pretty sure that when the system boiled over, it vented through the filler cap so expect to find sticky greenness over everything which won't be good for the electrics at all.
Moral of the story - if something don't look right, it probably isn't!
Pics to follow, if there is anything worth photographing.
Last edited by PaulLipscomb on Sun Jun 29, 2014 8:36 am; edited 2 times in total (Reason for editing : typos)