A while back I was at my yamaha dealer, picking up some valve shims and such for my yz400f, and the parts guy asked me if it was for a yz or a wr, i said a yz. Next thing, he warned me about them bikes, you either have to be accelerating or decelerating, or the crank will go into a harmonic imbalance or somthing of that sort, and said the bearings on the rod will basically self destruct. He said you shouldnt be cruisin at a steady speed or your crank will go. Is any of this true? That scares me a lot cause theres a kid that goes to my school that has supposedly put 2 cranks in his 98'. Now when im riden on big open straights or anything, im always paranoid and i speed up and slow down slightly but constantly. Is this total BS, or is there some truth to the cranks going on these bikes from just putsin at steady speeds?