I just bought a 2007 yz450f and have no history on the bike. I'm pretty new to mx and even more new to four stroke bikes so please help! The bike is stock as far as I know other than an FMF pipe. I have rode the bike for a couple hours and it runs strong but stutters a lil bit at lower rpms. What should I do as far as maintanence before I ride more and how can I fix this stuttering issue? Any advise would be greatly appreciated.