Tilo Niebel and his gents at the Harzer Bike company in Germany, upon finding they had a tank engine to play with, decided that of all the more reasonable things they could build, they should ...

If in case water gets mixed with petrol ... You may check out the following article for more details: Bike maintenance tips for monsoon.

NO, the water doesn't gets inside the fuel tank. I know there is a gap between the lid and the brim even after closing the lid, but the lid has a rubber washer which seals the petrol tanks mouth.