The more and more I read some of these threads and post I get more disgusted... Some of you guys treat these paper weight mass produced crappy engines as if they were NASA's latest invention..""THERE NOT""".... I read and watch how some of you guys spend all day and night thinking that you are the one that is going to and has discovered some ancient Chinese secret and are going to build a 200 HP engine with one modification that only you have discovered....Its not worth it,, believe me and others we have all tried and thought of everything... ""JUST KEEP IT SIMPLE"""... If your that serious then buy a used CR, KX,or KTM 60 dirt bike and take the motor, pipe, carb, ignition and mount that in a frame with the gas tank and motor mount all ready incorporated and there you have it.. you will have a 14 HP engine that is water cooled and you can even shift 5-6 times sparing you the $200 jack shaft kit and you also get a nice pipe and carburetor already jetted... for the money and performance this is the best way to go.... some one once told me (JAG) that are you really going to notice that %5 percent difference for all that money and work just to lose reliability and %5 percent power somewhere else on the power curve.... Yes, I know this is a great HOBBY for us MOTOR HEADS and tinkers,, and its not for everyone... BUT COME ON MAN !!!! KEEP IT SIMPLE and FUN and DONT OVER DUE IT and FALL TO PIECES ..... ride safe and have fun in the end !!!!!PEACE, and ride it like you stole it !!!