Im in the process of fixing up my 03 burgman 400 and i have noticed that the round black doughnut looking seals on the forks are rusted..They seal the area where the "shiny" part of the fork slides in and out of the lower portion of the fork, and i'm assuming the two seals are there mainly to keep dirt and water from entering the fork, but do these seals also contain an oil down in the lower section?? I mean i know there is fork oil inside of there but i wasn't sure if these seals are the only ones holding the oil down in the shocks when they are compressed..Does anyone know how difficult it is to replace these seals? It appears as though the entire fork has to be disassembled... They are not rusted badly but you can see that its like a metal ring that is encased in rubber which makes the seal, and i can see the metal ring under the rubber is starting to rust and the rubber is cracking so i can see the rusty metal in certain spots. Is this a common failure on a burgman?