i was washing the bike today and noticed a crack in the paint on the oil tank where the dipstick / filler stem is welded to the tank. i put my glasses on  and had a closer look and the paint has blistered around the other side of the filler tube as well but hasnt cracked yet.  i reckon there must be a pin hole in the original weld that is seeping oil or fumes under the paint. The bike was painted 3 years ago and the rest of the paint is still smick. I am thinking of cutting the paint off with a sharp knife below the blisters and scraping it all clean and sealing the weld with something and touching up the paintwork but i am no fukin artist. or painter. anybody got any ideas?