I recently had my 81 invader at a mechanic because of fouling issues and he seems to have taken care of that for me but he noticed that the clutch seems to be sticky and doesn't want to let the motor wind up sometimes. Is there a way to free this up without tearing the clutch apart? or could there be another cause to this? I am new to working on sleds and am trying to do as much as I can myself. Any help you guys could give me would be greatly appreciated. Thanks