i have posted about this in the past but still have a problem. my 03 yz450 has a severe vibration in the motor...no it is not loose triple clamps...but in the mean time i have properly replaced the crankshaft, cylinder, piston kit, timing chain, and a primary drive gear that goes on the right part of the crankshaft, the only things that i didnt replace was the transmission which was in perfect order, the stator, balancer shaft, and clutch which also all look in perfect condition.. the most popular response to this is the balancer shaft but i bought one and compared it to two other ones and they all look identicle, no cracks, bends or anything. could it be something up top in the valves or valve springs? im not saying its not the balancer, but i just dont see how it can be, but i will put the new one in, but just in case that doesnt work, i need some suggestions please. by the way, after all those parts were replaced i lost most of my power in 4th gear, and nothing was done wrong, that is a fact. the severe vibration is mostly in the higher rpm's of each gear, as well as in neutral when reving it. but still has all the power in 1,2,3 but just not 4th.