i have a 97 kx 125, while i was riding i went over a jump in 2nd gear, when i went to downshift when i had landed, i did so and my bike would not go into gear. Upon further inspection, i looked at my gear box cover and noticed it had a crack in it and had oil spilling out. When i took off the gear cover it appeared that it got broken because there was a warn groove in it. so i got a new cover and i'm hoping that is all that is wrong with it. Any ideas on why the gearbox broke? I was told that it was thought that the pinion was broken, but when i opened up the bike, it was not. But when i opened the bike and moved it, two small metal balls fell out onto the ground. any ideas on where those go and what they are?