Are the plastic horseshoe shaped pieces on the crank replaceable, what are they there for, and why do you suppose one side melted in two small palces? The bottom seized but not the bearing, the plastis piece on the right side broke off on the ends and jammed up the lower end. The cylinder had just been replated at Eric Gorrs and the engine had about 4 hours on it. The lower end had not been done and it was due anyway. I want to rebuilfdthe crank rather than replace it. Any yamaha experts out there? Thanks in advance. P.S. If you are parting out a 97 YZ let me know. My email is JCANDE5@AOL.COM