Registered Forum User
Ducati Corse
Posts: 3,134
Join Date: Jan 2002
Location: notts
Mood: Bloo and Yellow.. and Red now ;)
As above. It's best to replace as a set. You'll only accelerate the wear keeping the old chain on.
As for gearing......... are you happy with what you've got at the moment? Most common change is 1 tooth off the front, to a 14T.
If you're going to remain with the stock type of rear sprocket you're stuck with only a couple of options as there isn't a great range to choose from unless you go DP and these are very expensive.
If the bikes a keeper, then it's worth considering a Renthal carrier as future rear sprockets will work out cheaper. You also have a large range of tooth options to choose from.