Toolfreak, I did notice something in a pic of the bike. The 856 uses a top pull, top swing, front der. If you replaced it with a der. that the clamp is lower than the original spec this may have something to do with it. I am kinda stumped here this problem should not occur. I don't see how the rear swingarm can hit the cage. A lower positioned clamp on the front der. may be contacting the spot where the swingarm mates to the frame. I don't know I am just guessing here. I hope you solve this.