Use the tool kit pin spanner...

...to loosen the header/muffler collar nut. It does not come off the muffler; it just needs to be loosened.

Use the 12 mm and 13 mm wrenches the loosen the header pipe mounting clamp.

Use a dead blow hammer or block of wood and hammer to knock the header pipe free of the cylinder head and muffler. Use care as the pipe can easily be deformed if struck too hard.

Slide the header pipe free of the mounting clamp and set aside where it will not get damaged or stepped on.