look's like it was being worked on there is a axle stand near it on bit's of wood possibly to lay on or chuck on to it! And it is has a gas tank on it !
the top one isn't one of mine (well it is but another one) the 2 standing up and bottom one are off bolly, the 4th is in the van as a spare, the "yellowy" one is a crappy one i got as a spare originally.
or if you mean the bog rim...... i'll go and flush it. if it's yellow let it mellow if it's brown send it down