I had a very tiresome 300 mile ride yesterday in cold, heavy rain. I couldn't believe my eyes when I removed the tank bag to fuel-up and found the filler cap about 5mm below the trim. I was a right bugger to get the cap open due to the vacuum. Seems the vent pipe is totally, and I mean totally, blocked.
The pipe is completely free and not crushed for as far as I can see it without taking the trim off so I am sure I haven't trapped it. And, this fault was not there on the 300 mile outward run.
I can only imagine some crap has been sucked up the pipe - I will find out at the weekend. Meanwhile, anyone else had this?
P.S. good news is that after 20 mins the tank regained its correct shape.