Some kind of fuel filter

[SteveW]

My 550 K0 tank is completely empty and bone dry inside as I’m in the middle of painting it.
Just looked inside the tank with a torch and pulled this stuff out.
My tank has the fuel filter in the bowl below the petcock so no idea what this stuff is.
Its almost like duck tape without the glue.
Any ideas, I’ve had the bike 8 years and never had any fuel issues with it.

[McCabe-Thiele (Ted)]

Could it be that the filler cap has been masked off in the past for painting & somehow it ended up inside the tank?

[SteveW]

Could it be that the filler cap has been masked off in the past for painting & somehow it ended up inside the tank?

I think you are correct Ted, I'm pretty sure its some kind of duck tape that the petrol has dissolved the glue off over the years.
Amazed it hasn't caused a problem with the fuel delivery, I've had the bike 7 years and no issues.

Tank was blue when I got the bike which is a non standard colour, so it has been painted at some point in its life.