You'll need to be more specific. What do yoyu mean by "the gear on the crankshaft keeps shredding" ?
Are you lubricating the gears?
There is no tool for the flower nut except for a screwdriver to remove the locking screw.
Improper clutch adjustment won't cause gear failure. Something else is wrong if you are seeing failure of the primary gear. Either a bent crankshaft or improper mesh between the primary and secondary gears.
I've had bad primary gears that were drilled off center and not concentric with the gear teeth. They wobbled. They were noisy and would have probably failed eventually if I had not replaced them
Tom