I'll show you how to do it.
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Sandpaper and a file
A flathead screwdriver
A piston stop
A socket wrench with a 17mm socket and a sparkplug socket
Step 1: What's wrong????
When the clutch is together, it moves up and down the notches in the clutch bell, and after time it creates burrs in there. When those burrs get big enough, they hang up the clutch and it don't work no more. :(
Use a file on those notches of the clutch bell, if you have big burrs, just to get it smooth again. Then finish it off with some 220 grit sandpaper. Do the same on the clutch plates if it's rough there. You might need to lightly sand those spots in the friction discs as well.
When you think it's good, put the clutch pieces together and squeeze it to see if it moves smoothly. It should.