Finished my 520 chain and sprocket upgrade on my 998 tonight and I am looking forward to a test ride tomorrow. Specs as follows: DID 520 chain AFAM quick change rear sprocket hub AFAM 39 tooth steel chain ring AFAM 14 tooth front sprocket AEM star drive flange EVR front sprocket cover I kept my cush drives as they appeared in pretty good shape. I also picked up a Ducabike aluminum rear sprocket side nut, which looks really nice, but I was nervous about trusting the aluminum and I put the steel nut back on. I will report back on the change the sprocket sizes make.
I know the 520 is not necessarily an upgrade, but the sprockets definitely are. I am a pretty tame rider and not likely to be WOT often. I plan to keep a close eye on chain wear and I can always go back to 525 if it doesn't work out.
Got in a nice test ride today. RPM seems to be up by about a thousand in a given gear with the new sprockets. It definitely helped to keep the revs a little higher and smoother. It also enhanced the always awesome freight train pull that I love in the 998.
