I have a Honda Varadero 2010. When I fill her up to max, the level of the liquid in the tank is at maximum, just a tiny bit below the rim of the nozzle. Then, I poor in some more and the level raises up to the nozzle but afterwards it drops again just to the original maximum!
So I repeated this exercise a few times and the tank seems to be made of rubber. I put in about ten such "additions" and each time with the same effect. (Then, I realized that it might be bad for my beauty so I stopped.) There's no leakage or anything and the bottom of the bike is as dry as my bank account at the end of the month.
What is all that about? Does Honda make a magical, bottomless bikes?!