This is a COMPLETE 428 conversion kit by Renthal. It contains the front and rear sprockets AND the chain. All matched to allow you to easily switch from the stock 520 setup to a 428 setup. Why would you want to do this? A lighter final drive allows puts more horsepower to the ground. Your bike will feel like it has more power with a 428 kit because it's using less of it power to pull the final drive gears and chain. A must have.
--- Gearing is 16T (front) and 61 (rear). Chain is Renthal R1 Works non-O-Ring ---