I have a D.I.D 525 VM2 chain in ready standby, that is the same kind of chain that was specified in my owner's manual, I bought it online for $110 if I remember right. The chain I have on the bike right now is a generic Parts Unlimited X-ring chain that only cost $90, and is doing fine passing 13,000 miles. About the only difference that I can see between the two chains is that D.I.D. incorporates an anti-rust surface treatment on the plates, that's really about it.

Try:
http://www.parts411.com/acb/showdetl.cfm?&DID=9&Product_ID=28035&CATID=24

That's where I bought mine.

Michael D. Rodriguez