vlad is definetly right on!!!
i have never had a bearing issue (knock on wood) but i do check afterevery raceday. i make sur that the spur and ring gears are square, alittle more slop than a paper width, and about .5mm-1mm slop on the clutch bell and there is room between the clutch bell and the flywheel...thats all i do and had great luck. hope all the info here helps...good luck