I just changed out my rear sprocket to a new sunstar aluminum 39t sprocket, a steel 15t in front, and a DID roller chain and it feels like a new bike. I cleaned all the gunk in the front sprocket and it blew me away. The whole process was maybe 30 minutes. Piece of cake with a haynes manual as well as general know how of doing these things. I also changed the grips with the ol hairspray trick and they aren't all split and cracked now. I just have to do the exhaust and a rejet and I'm about done with the bike.
Keep in mind that you're gonna have to clean and lube that roller chain MUCH more often than an o-ring, if you want it to last! (Speaking of which, I gotta do my chain tomorrow)
Yeah, I know, but its way easier to take it off and put it back on than wanting to spend a whole load of money on an o-ring chain right now. The wife had a surgery so I am trying not to spend as much on the toys right now.