Check for dowels on CMSNL...
A dead blow hammer ( and protection ) may be enough to crack the casing.
Find dowel positions and tap in those areas using wood and a small hammer.
Any movement, even slight ?
Tap casing back on and repeat.
DO NOT tap in a screwdriver or chiesel or anything else for that matter between casings.
The gasket will tear and release its grip.
You may have to gently walk the casing off bit by bit, but any movement is good. Tap the cover back on and retry.
Bike on centre stand with engine hot. Start engine, rotate back wheel in correct direction as fast as you can, clutch lever pulled in to handle bar ( clutch disengage position ) and drop into gear.
Blip throttle to introduce transmission snatch...clutch will eventually free.
A higher gear would help.
Just make sure the bike cannot roll off the centre stand. If it does the bike will shoot off either into your swimming pool or through the nearest huge plate glass wind.
Hot oil and transmission snatch is by far the most gentlest method of freeing a stuck clutch of this type.
Much much much less chance of needing a dentist.
Just take your time.
I hope your Gunna flush out the engine internally and examine the oil pumps filter screen...
Hot oil and saucepan method works on all sorts of stuff like non o ring type chain servicing, stuck piston rings in removed piston, Cox cylinders, merco bearings, etc etc. Etc., At least for me.
Never had a burn or fire yet, hot oil or petrol, but I know the dangers.
However SodS law says....if it can happen, one day it will.
I am extremely carefull.
Loop copper wire through that large hole in the stuck clutch plates, like a lace, to allow easy hot clutch plate removal from the hot oil. You can always leave it a while with the saucepan lid on for a while to cool down all by its lonesome....
Only heat oil until the first hint of smoke, then turn heat off.
Obviously heat the oil outside with no rain/snow in the weather forecast !
No pets, kids, or any d+£#@55£5 anywhere near that hot oil.
Safety first...
Dd23🤓