Auto clutch with 2mm of meat- grooved cover
 

I have a Peace Sports 110 that feels like the clutch is slipping and gets worse as it warms up. Pulled the side cover and the clutch and found it is a 3 bolt clutch. The clutch measures 2 mm of meat on the arms but the clutch cover has grooves that correspond with the friction plates. Is the housing supposed to have those grooves? Do the arms have enough friction material on them? Someone has had this apart before.

Thanks,
Randel