Just a heads up, Pexmor is the distributor of your 72cc, not a brand or type of engine.
To help you while stranded, do this.
Take off the clutch cover and see if A) The Philips screw in the clutch plate came out and as a result, tightened your plate.
I want you to remove the screw and loosen the crap out of the plate to see if it will move freely. I then want you to lock in your clutch lever, and on the magnet side (as it will be easier) see if you can move the crank by turning the nut. Assuming you have the stock M8 nut on the magnet, it will be a 14mm socket. You can also try this on the small bevel gear.
Try moving the crank manually once the plate is loosened damn near all the way.
Disengaging the clutch allows the crank to move freely without the bike moving, just as disengaging it allows the bike to move freely without moving the crank.