maybe the clutch shoe is stuck on the the clutch bell. try spinning the clutch bell when the engine is not running. it should spin freely. If not, then you have a stuck clutch shoe. Remove the clutch bell and clean it together with the clutch shoe or better replace the clutch shoe. It usually happens when yoe have a burnt clutch shoe. try to have a clurtch shoe with vespel material. it has a lower coefficient of friction than std and therefore allows the clutch to engage at a latter point.