Yeah, that sounds like a starter clutch slipping to me also. But when you say "clutch basket" it sounds like your talking about the clutch that you operate with your left hand.
Bear in mind I'm not familiar with your modal. The starter clutch on my bike is on the other side of the engine of where the drive clutch is.
Purchased new in July 2006, 0 miles.
Miles as of January 2019 102,137 miles