The clutch shoe assembly retains the sprocket on most chainsaws. In almost all cases this also has a left hand thread, so undoes to the left not right.
As you are already aware the assembly is attached to the crankshaft so it is almost impossible to remove by hand because everything goes round together
There are commercial piston locking tools available to help with this job but I DO NOT recommend them (I've seen them fail :( )
The fastest way to remove the shoe is with an air (or lithium) wrench and the correct tool to lock into the clutch so as not to damage it.
I really recommend that you seek out your local Garden Machinery dealer and ask them to do this small job for you, they will have the kit and have it done in minutes.
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