It's very possible that the guy didn't know shit.
The Banshee motor is a very simple one. First thing you should do is buy a Clymer manual. It will show you step by step how to do pretty much everything you need to do to your bike. For everything else, there's BansheeHQ.
You need to pull the clutch cover and inspect the clutch components. Here is a pretty simple order of things to do.
1. Drain the tranny oil and coolant.
2. Remove the brake lever, foot peg and kick starter.
3. Remove the clutch cover bolts.
4. Remove clutch cover.
Now you're in.. The clutch components will need to be inspected for wear. The pressure plate, inner hub and basket should all be checked. Depending on how old the motor is, it may be time for all new parts.