yz 450 sputter at low throttle
I recently got my hands on a nice 2008 yz450, but I have a question. The guy i bought it from put an after market slip on on the bike and said he had it jetted. I am wondering if it was maybe not jetted properly because at low throttle it will sputter and act like its not getting enough gas. When i first rode it i thought maybe it was where it was cold. (40 degrees) If you get on the gas an open it up a bit the sputter goes away, but at times when u let of the gas it will backfire. What are everyones thoughts? Im thinking maybe it needs to be rejetted? I am new to carbs I usually run FI bikes so I am more accustomed to power commanders as apposed to carbs and jetting. Also would this make it difficult to start?