I second that.I would just get a new rim and also some washers and E clips/retaining clips. Sometimes the clips and washers like to take flight
http://www.sawagain.com/standard-7-spline-rim-sprocket-3-8-pitch-7-tooth/
http://www.sawagain.com/stihl-sprocket-clutch-drum-washer-and-e-clip-lot-of-6/
That one is pretty bad and I wouldn't want to put a new chain on it.
Those clips do like to go flying. I set the clip in the slot on the crank, then place the wrench endnotes a swrench over the clip, then just tap it in. The other way I like is with a set of diagnal cutters or needle nose, place the clip in the slot, then one end of the tool into the hole in the end of the crank, other end over the clip, then squeeze, done.
How are you buddy, hope all is well.
Got me a 540t a bit ago, needs the on off switch replaced, but runs great. Wrap handle is a bit loose to at the point it meets the top handle. I figure they will both be fixed at the same time.