This is on my 04 450. I bought the bike a month ago from a good friend. I was checking the valves this weekend and noticed that where the tank sits in the frame it(the frame) is being wore down considerably. There is also wear marks on the side where my rad covers are making contact with the frame. Is there supposed to be anything between the tank and frame? It has the rear rubber cushion and i was able to adjust the tank up off the frame when i re-assembled.