I Just got a ttr 125 2002. I know it needs some work and I like the project, but I could use a hand in identifying some parts and a possible serious problem What is this gear called in pic one I dont think this gear is supposed to come out, and whats inside is sheared off. Is this repairable? There also looks to be a small crack in casings, about exactly where my marker is. Its hardly noticeable. Is this a huge concern?