Had to do this on a buddies Harley… Tried the ‘cut a slot’ method for a flathead too…broke the screw head in half trying to take it out. Drilled it out, head popped off, and was able to take the shaft out by hand. Those screws are made of play-doh…not metal.

First oil change on a new to him bike but some numbnuts but the crank case cover bolts in like a gorilla…torque spec is 7 ft-lbs(9.5 Nm). That’s like a quarter turn past finger tight. It just needs to compress the seal so oil doesn’t spill out.