Replace or upgrade your worn chain and sprockets with this market leading sprocket kit featuring quality JT Sprockets and D.I.D chain brought to you by THS Moto. Note the chain may need to be adjusted to length using a chain breaker tool. This Sprocket Kit contains a 13 tooth front JT sprocket and 49 tooth rear JT sprocket with a 520VX3116 116-Link 520VX3 FJ X-Ring Solid Bush clip DID Chain Fits: Yamaha YZ450F 2007-2013 2015-2017 2019-2021