2005 yz 144. I got the bike a year and a half ago. I never toucheed the jetting. Bike has always started up first or second kick and ran great. The motor blew on it and had full top and bottom end done with maybe 20 hours if even that on it. After rebuld bike ran really amazing. I weight 200+ with gear on and the front end would wanna come up some. All of the sudden the bike just is not running right. It has a powerband but no "hit" The bike is just down on power. I had to replace the right powervalve and i had it re grinding to fit the 144 cylinder. its not a percet match of the left side but its not bad. When im riding the bike, say just crusing down the road with quater throttle the bike is almost sounding like its loaded up but its not. If on a stand and i rev it, it sound totally crisp and fine. I guess the best way i can descrbe the power issue is it almost feels like the clutch is being held in slightly and i cant get full power. I can literlly hold the bike wide open with clutch pulled in in a corner and not worry about something happening. I cleaned the jets twice. Put fresh gas. I put new clutch spings in and measured the fibers and they were just in spec. I put a new plug in I have never fouled a plug in teh bike but once in a year and half. I fixed the powervale problem also i had. I really have no clue what is going on here any ideas i appreciate.