Tuflek,
If you have dropped something down the cam chain tunnel,it is a simple job to take the L.H. side engine cover off.you will have to remove the exhaust pipes first.Then right there in front of your eyes you will see your lost part sitting on top of the chain sprocket on the engine.I used to own a fe400(99) and in the time it took everyone to reply to your post you would have the job half done.....nsman