Hi guys, Just put about 6 hours in my brand new 2012 KX2050F. Is my first NEW bike and I'm planing to maintain it by the book (well not by the manual and replacing the piston after 15 hours, cause I don't race it that hard). One thing that's missing from the book is replacing interval for the cam chain. Someone recommended changing it at 20 hours interval. Other manuals (yamaha) say to check and replace if needed. What do you do ?