As a general rule Performance Clutches have extra surface area, some also do away with the OEM Rivetted Spring Plate. The benefit of the OEM Spring plate is it acts as a dampener or cushion to help release the clutch smoothly & quietly. The dis-advantages associated with the spring plate is that when it fails it often damages the Clutch hub, clutch basket, clutch bearing & clutch plates.
Another dis-advantage of the spring plate is that it takes up valuable space in the clutch pack – Removal of the spring plate allows for additional clutch plates that provide greater clutch holding power. More Clutch surface area & no spring plate equate to enhanced clutch performance albeit a slightly noisier clutch.
As a rule the clutch hub bearing should be replaced when the clutch pack is serviced, a lot of times the clutch bearing goes bad but it is not noticed until you fit a performance clutch – this is because the riveted spring plate that fell apart has been absorbing the initial shock when the clutch lever is released. We have had incidents where the clutch hub bearing has failed at under 10,000 klms.
The Harley clutch does not have any cushion springs on the basket itself to reduce noise – if the spring plate has damaged the hub or the basket and it is pushing the clutch hub or basket off center, this can also contribute to the noise level. While the clutch plates are disassembled, grab the hub or the basket and if you feel any movement, that is an indication of a worn bearing which can create a squeal or growl every time the clutch is let out.