Thought you may want to read this post from another forum about clutch problems with some Sporty models that sounds similar to what the OP is experiencing.
Clutch Alert!
Just a head's up on a real problem with the Sporty clutch. The stock design uses an additional spring plate in the center of the clutch pack. It is a double plate with small springs between the main plate. These plates are all held together by brass rivets.
Those rivets are the weakest link in the entire drive mechanism
Turns out that is EXACTLY what happened to mine at 15K miles. It's 3 years old I don't think it was under warranty. I took it to California Choppers here in San Francisco. They had it less than day, Cost about $500+ to get a new clutch and parts installed. He put a stock clutch back in, he said he had issues a couple of times with the Screaming Eagle clutches. I had him put allen wrench scrwes on the derby so I wouldn't run it the stripping torx issue again.
If there's ANOTHER clutch on the market they someone thinks is a good replacement, I'd like to hear about it.