In time even the main part of your clutch assembly, the clutch basket itself, needs replacement. A high mileage alone can cause cracks in the material, deformation due to centrifugal force and the clutch cluster circlip groove becoming worn and imprecise. The basket of your clutch should be checked for wear or damage during every service of the motor and when necessary, be replaced. High end sport/race clutch basket assemblies should be used for more performance orientated motor tuning projects.
SIP-TIP: Do not forget to order a new castle nut, safety washer, thrust plate and a pushrod. New clutch friction plates are also recommended when doing this job.