With the engine off and someone sitting on the seat operate the switch and check for voltage at the connection for the clutch. Do you have voltage? If yes, you getting power to the clutch. Turn of the switch and ignition. Using a volt ohm meter check for resistance (ohms) on the clutch. I would expect to see around 2 - 4 ohms. If zero or infinity your clutch is bad.
If Ohms check out try checking the air gap between the clutch friction plates. this should be around .010 inch. Most clutches have either three or four adjusting bolts on them. these are usually self locking nuts with a spring behind them. If gap is to wide carefully adjust the gap to .010 in all test openings (3 or 4). Now try the clutch, does in clank when you flip the switch.
good luck
Roy