After much research/reading: another overheating thread

I know this topic is beaten to death, as I've read every thread I can find on it. Just got my 06 VFR about a month ago, and I was fine until I ran into traffic.
My bike turned into a coolant barfing machine, and I'm trying to figure it out. Sorry for the length of the post.

[ambient air temp was ~65 in all of this]
The first time I reached ~240 sitting in traffic, and had the terrifying experience of coolant all over the road/shoe/back tire, I've been experimenting.
- The fan has always kicked on at 211, like clockwork
- Runs at 180-200 when riding around at 30-60mph
- 0-15mph for more than few minutes, 230+ temps, even if I park it

Attempt to address it:
- Replaced radiator cap
- Completed the 'burping' exercise, topped everything off with 50/50 coolant (sulfite free)
- Took it for a very slow ride (10-15 through neighborhood) to get it to heat up again (knowing this is the weakness of the radiator/fan setup, triggered in traffic).
- Reached 230 and it just stayed there (not exactly worried at this point). Went home and let it idle for a while to let it cool off.
- Stayed at 230 idling for 15 minutes before I shut it down.
- Only saw a drop of coolant from the overflow line (a little concerned, it should go back to 210-220)
- Could have been barfing while I rode (it was dark), because the right radiator was basically empty when I pulled the fairings (now very concerned).

Shut it off, let it cool off for a few hours, then re-burped & topped up between min/max lines.

- This time, I left the fairings off, and let it idle in the garage
- First heat cycle (200->fan->210) was perfect
- Next heat cycle, it went 210->fan, then climbed to 230 and stayed there
- Over about 10-15 minutes, the coolant tank slowly filled, and proceeded to barf pretty much the entire contents of the radiators (right side was empty after I let it cool off).
- Radiator tanks are gurgling like crazy, sounds like the bike had too much whiskey and cheap tacos
- Oil looks clear, what coolant is left looks clean

So in conclusion, my question: is this typical of thermostat issues? I'm surprised by the propensity to barf coolant, it worries me I could have a head gasket issue (especially the gurgling), but I see no signs of fuel/oil contamination in the coolant. I don't quite understand how it's sitting at 230 for a while before suddenly filling the coolant tank and puking out the contents of the radiator, seems like too much pressure for simple liquid expansion.
I just want to be sure thermostat is the best diagnosis before I tear everything down...clearly a time consuming job, for someone who hasn't worked on this bike before.

Assuming it is thermostat, suggestions for better alternatives to the Honda part (assuming from other threads this is not the best)?

 

Wow, quite a dramatic overheating issue. My first reaction is a radiator cap. It seems as soon as there is some pressure build up the cap can't handle it and blows coolant into the overflow tank. But you already replaced the cap. Did you tighten it completely? Just had to ask...
If that's ok then the thermostat is the next thing to remove and test. If anything it sounds intermittent - which is unusual.
Remember the temp you are reading on the dash comes from the ECT sensor in the front cylinder head. It's not the temp that is turns on the fan. The fan switch is in the left radiator.

The barfing comes from the coolant boiling. Without a radiator cap holding pressure the coolant will boil at a much lower temp.

So my best guess, given a good cap and a water pump that works, is a stuck shut thermostat. IMO that's not the usual way a thermostat fails - but they certainly can!

 

thermostat can certainly be stuck partially open which won't allow full coolant flow and cause symptoms such as yours. Oil in the coolant and vice versa is not a guarantee that it is not a head gasket. a head gasket can blow in many locations that wouldn't result in a cross contamination.

try swapping the thermostat first

 

FWIW a fresh fill of brand new coolant did the trick. The dealer said they had just topped it off (could have been old/stale) and when I topped it off, it was some coolant off my garage shelf (who knows how old that was). Ever since a full topoff of fresh coolant, it's been performing as expected. <whew>

 

Weird. I was betting on the stuck thermostat....