KTM sells an oil made specifically for the 50LC, I believe that it's called K-Racing oil. The clutch in the LC has tiny little cupped washers that act as springs. As the motor revs these cupped washers will flatten out and engage the clutch. As the clutch wears, all the clutch material will get trapped in the cupped washers not allowing them to flatten out anymore and your clutch will slip. The springs must be cleaned on a regular basis for optimum clutch performance. The clutch works the best with an outer diameter (from clutch shoe to clutch shoe) of aprrox. 82mm, as the clutch wears it becomes smaller therefore you must shim the clutch shoes back to 82mm for proper stall speed and engagement.