I have a jackshaft assembly and went to start my bike and noticed the nut on my spindle backed out causing the whole guts loose and bearings hanging out. I stripped it down regreased the bearings tightened it down just enough so the spindle moved easily. I road about six miles when the bike quit. I looked down and the nut had backed out so far it was against mt sprocket and caused the motor to quit. Do I need to just change the bearing set only or the spindle also?